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5 Steps to Propel Your Chemical Engineering Career

Chemical engineering combines experimental and natural sciences like physics and chemistry and other sciences like microbiology, biochemistry, biology, together with mathematics economics all of these to develop, transform and manage the industrial processes that run raw materials into valuable products. Chemical engineers are in high demand increasingly daily as the world’s technology advances. In this post we are going to look at the basic requirements for a chemical engineering career.

1. Solid Educational Background

The requirements for a chemical engineering degree in tertiary institutions like American International College is normally a very strong educational background in mathematics and chemistry whereas knowledge in the other sciences will be an added advantage. At the time of your undergraduate studies try to pay attention to getting fundamental knowledge in reaction engineering, thermodynamics, process control and fluid mechanics.

Besides this you might want to consider pursuing an in-depth degree which will highly improve your skills and even open more ways to a great chemical engineering career.

2. Gain More Hands-on Experience Through Internships

After having a strong educational background you then move into the real world and see things on site how they actually work. This is where internships come in for a chemical engineering student in chemical engineering companies and research institutions by providing valuable work experience to a student by working on real projects in these industries.

3. Develop and Nurture Skills

As a chemical engineering student , you should develop new skills for your career. If you take time and develop on your soft skills like teamwork, creativity, communication, problem solving, adaptability and work ethic then this will likely propel you to a better position on landing a job. Make sure that you keep yourself updated with chemical engineering tools and software.

4. Stay Updated in Industry Trends

Chemical engineering is a very diverse field of engineering. Sometimes back, people used to call chemical engineering a universal engineering career for the reason of its technical and scientific mastery being so broad and covering a wide range of science branches. As a chemical engineer it is absolutely necessary in the current times to be updated with new technology.

It pays as a chemical engineer to stay ahead of the job market and learn new skills that will be of great help in the future. Chemical engineering is in the middle of many different industry categories and since each of these categories keep on changing to keep up with the state of the art, regulatory policies and stakeholders, chemical engineers have to stay in the lead with the field.

5. Acquire Professional Relationships and Networks

Networking in any career department is vital for any individual. Landing a good paying job is not easy even sometimes with papers and knowledge and skills. When you get the chance, talk to different types of professionals and form meaningful relationships with them during your studies and even your internship. Building this professional network will guide you to finding a good job.

Endnote

As a chemical engineering student you need patience, unending education and dedication for you to enjoy the road to your achievement. Take advantage of challenges and learn from them, don’t hurry processes and go with the flow. 

Introduction to Molecular Ions

Hello friends, in the previous tutorial we learned about ions and now I am coming up with a new article Molecular ion. In this article, we will discuss the formation of molecular ions. When we discuss molecular ions many types of questions arise in our minds. I hope after reading this article you can answer these questions which are given below:

• What are molecular ions?
• How many types of molecular ions?
• How molecular ions are formed?
• Why is NH4 + not a molecular ion? Give a reason.
• Which type of molecular ions structure exists etc.?
• Which example is suitable for molecular ions or not?

Discovery

In 1794, molecules were considered a minute particles according to the French. Latin used vogue words for molecules until the late 18th century. Molecules have evolved as the knowledge of the structure of the molecule that retains their composition and Chemical properties according to the earlier definition was less precise. This concept breaks down because most rocks, salts, and metals are composed of a huge crystalline network of chemical bonded atoms or ions.

It reveals the existence of strong chemical bonding between the atoms of molecules in ionic form.

We are searching for many years on molecular ions, including helium hydride ion, the first molecular ion we discovered that was formed in the Universe by a chemical bond. We detect it in the laboratory by inserting a medium. It was first seen in a planetary nebula named NGC 7027 using the GREAT spectrometer aboard the Stratospheric Observatory for Infrared Astronomy.

I will make this topic very easy for beginners.

So first of all we see its overview :

Molecular Ion:

By gaining and losing electrons of an atom, the molecular ion is formed

The second name of the molecular ion is also known as polyatomic ion which is formed in radical cation by a covalent bond by sharing more than one electron.

It is an example of a radical cation.

An electron is a light particle as compared to a proton.

Molecule:

it is the smallest unit of a substance and is formed by the combination of atoms.

It may contain one or more atoms.

Some examples of molecules are

• H2O (water)
• N2 (nitrogen)
• O3 (ozone)
• CaO (calcium oxide)

Difference between molecules and molecular ions:

Ion:

ion is formed by the gaining and losing of electrons of an atom.

For Example :

To understand this topic we see the example of sodium chloride NaCl.

Na+, Cl-

Difference between ions and molecular ions

Molecular compounds

• When an atom of two or more elements share electrons a molecular compound is formed
• It is also known as covalent compounds.
• In molecular compounds, the ambivalent bond is formed when atoms shared their electron pair.

Molecule ___gain/lose electron _______ molecular ion

• Types of Molecular ion:

There are two types of molecular ions:

• Cationic molecular ion

They have charged positive ions because they lost the electron from the molecules.

For Example :

CH₄⁺

• Anionic molecular ion

They have charged negative ions because they absorb the electron from the molecules.

For Example :

O₂^-I

The main differences between cationic and anionic molecular ions are categorized in the following table:

NOTE:

Cationic molecular ions are abundant in nature as compared to the Anionic molecular ions.

Rules of writing:

• In the naming of molecular ions, caution is written first and the anion is written in second no.
• Ion is written in the bracket if the formula unit contains two or more of the same polyAtomic ion with subscript written outside the bracket.

How molecular ions are formed?

These cations and anions are formed by the bombardment of high-energy particles such as electron beams in the form of alpha particles or X_rays. These rays or radiation knocked out the electron from gas molecules resulting in the formation of Cationic molecular ions.

Simply we can say that it is formed by the ionization of the molecules.

For Example :

N₂ + 1e^- ___x_rays/alpha rays______N₂^-1 (molecular anion)

CO ___alpha/x_rays_____ CO⁺ + 1e^-1 (molecular cation)

Explanation :

In the first example, we deal with a nitrogen molecule in which it gains one electron in the presence of a beam of X_rays or alpha rays radiation and becomes a molecular anion. Molecular anions are less abundant in nature. To understand this topic we take the example of bags and clothes. If you put the clothes in a bag, if the bag is almost full then it is difficult to put more clothes in bags. This is the same logic apply to molecular anions.

That's why it is less abundant.

In the second example, we release electrons from CO, in the presence of X_rays then we format molecular cation because it is easier to remove electrons from more than one.

It is very abundant in nature.

• Features of formation of molecular ion:

There are important features that tell us how an electron is removed from bond pair:

• Electrons are easily removed from non_bonded pairs as compared to bonded pairs.
• Because bonded pairs are at lower energy levels and most localized as compared to non_bonded pairs.
• It is most difficult to lose electrons from bonded pairs.

The most important thing here arises is that,

Is Ammonium ion (NH4+ ) a molecular ion?

The ammonium ion is not a molecular ion due to its formation through the coordinate covalent bond between ammonia (NH3) and hydrogen ion (H+).

Because nitrogen of ammonia has electron lone_pair it can donate electrons to hydrogen ions resulting in the formation of ammonium ion by dative bond or co_ordinate covalent bond.

Hence, ammonium ion (NH4+) is not formed by the gain or loss of electrons. Therefore it is not a molecular ion.

NH4+ is a poly-atomic ion.

Is ozone a molecule?

Ozone is also a molecule that is bound by three atoms of oxygen. Which is symbolically represented by O₃.

Its layer protects our environment or atmosphere from harmful ultraviolet rays which are emitted by the sun.

Identification of molecular ions:

If molecules have any species of the charge they will be molecular ions if we remove the charge from the molecule then it is simply a molecule, not a molecular ion.

CH₄⁺ (molecular ion)

CH₄ (Molecule not a molecular ion)

What is the molecular mass?

The total atomic mass of all elements present in a molecule is equal to that of a particular substance known as molecular mass.

How can we measure the molecular mass?

We can measure the molecular mass of the molecule by using the following steps which are given below:

• First of all, we define the formula of a molecule.
• We find out how many atoms are present in a molecule.
• Then we multiply the atomic weight of an element by the number of atoms.
• Similarly, the same process applies to all elements in a molecule.

Example:

See the example of calcium oxide (CaO).

Sum up all the values we obtain,

CaO = 1*40(atomic mass of calcium) + 1*16(atomic mass of oxygen)

= 56 g_mol^-1

What is the formula mass?

The sum of the atomic mass of all the elements present in a formula unit of a substance is called formula mass.

For Example :

The formula mass of NaCl is 58.5 atomic mass.

Which type of force exists in molecular ions formation?

 

Intermolecular forces:

Intermolecular forces are electrostatic attractive forces between permanently or temporarily charged chemical species. They include

• Van Der Waals forces (attractive forces)
• Dipole-dipole forces
• Ion_ion forces
• Hydrogen bonding

Van Der Waals forces:

These forces are responsible for the formation of molecular ions.

Ion _ dipole forces:

Dipole-dipole or an ion-dipole force is an attractive force that resultantly comes from the electrostatic attraction between an ion and a neutral molecule that has a dipole.

A positive molecular ion (cation) attracts the partially negative end of a neutral polar molecule.

A negative molecular ion (anion) attracts the partially positive end of a neutral polar molecule.

Ion_ion forces:

Ion_ion forces are also known as ionic bonding. It is easy to understand this force is present between two oppositely charged ions. This force is not considered an intermolecular force but this force is helping us to understand this bonding.

A suitable example for this case is table salt, NaCl.

Hydrogen bonding:

Hydrogen bonding also plays a vital role in the formation of molecular ions. This force is stronger than all types of forces. Its best example is water in the formation of molecular ions.

How do you determine the molecular ions?

how to find the relative formula mass by using a molecular ion?

In mass spectroscopy, an electron is released from the molecule; then as a result we obtain a radical cation called the molecular ion (symbols: M•+, M+).

The molecules which removed the electrons resultantly gain molecular ions currently obtained the highest energy electrons

The Molecular Ion (M?) Peak:

We describe the molecular ion peak by using a graph:

In this peak, we can describe the relative formula mass (relative molecular mass) of an organic compound from its mass spectrum. It also gives us high-resolution mass spectra that can be able to find out the molecular formula for a compound.

In the mass spectrum, the ion which has the greatest m/z value is treated like a molecular ion. Some ionic compounds have mass spectra that don't contain a molecular ion peak because all the molecular ions break into fragments.

By the end of this article, you will be able to find out

Important Facts:

By using molecular ions we can determine the following facts:

• Determination of the molecular mass.
• Structure of a compound
• Kinds of bond
• Kinds of atoms

The most important question is what molecular ions how they are formed.

Significance/Applications:

Molecular ions obtained from the natural products on decomposition give information about the structure of the molecule.

I Hope, I cover all aspects of the molecular ions. It is the last topic of our first tutorial. If you want these trusting topics simply, give me good feedback for better results. If you have any questions, put them in the comment section. I will reply to you as soon as possible. Our next tutorial series is coming soon. Our platform tries to give the best and in trusting topics that clear your all concept. Thanks.

Introduction to Ions

Hello, students here in our previous tutorial we study molecules and now I am with a new topic “Ion” which might be possible for some of my readers this article seems to be new, and some of my readers may be familiar with this term. But no matter whether we know or not, in my article I try to cover all aspects of this term. Many questions arise in your mind such as you may think;

What is an ion?

How ions are formed?

What are the different types of an ion?

What methodology is utilized for assigning charge to an ion?

What are examples of an ion?

Which methods are used for the creation of an ion?

If my readers want to know the answers to these questions, hold copies and pencils in your hand and stick to my article till the end.

Brief description of an Ion

What is an ion?

Definition

An atom or group of atoms that brings a positive or negative electric charge as a conclusion of including lost or achieved one or more electrons

Or

A charged subatomic particle (such as a free electron)

By the word an Ion, it's not wrong to say that it is the type of chemical species which may hold two types of charges with some magnitude. These charges may be positive or negative with some magnitude. Those atoms or molecules that have unequal net charges associated with them simply say that charges on them are not involved in a factor of zeros, we use the term an ion for such types of atoms.

A short view over term atom.

Atom

As this term is the basis of chemistry everyone is familiar with this term. For understanding the article in a better way I explain it. Atom is the smallest component that constitutes the property of an element. An atom has a heavy central Part which is known as the nucleus. In the nucleus, two types of charges are present one is a proton carrying a positive charge and the other is a neutron neutral particle. Overall there is a positive charge in the nucleus. Around the nucleus, there are several circular orbits in which electrons keep moving the nucleus. In each orbit, electrons feel a nuclear pull that restricts their motion in a circular orbit.

Back to our statement that ions have a non-zero net charge. By non-zero net charges, it concluded that may an atom have more protons ( sub particle of an atom that consists of a positive charge. These charges are present inside a nucleus) than several electrons ( sub particle of an atom constituting a negative charge and present outside the nucleus, keep in motion in orbits around the nucleus) or secondly, maybe there are a greater number of electrons than the number of protons in their atomic or molecular structure. Thus we can say that a charged atom or molecule is named an ion. It is charged because we see that the number of protons and electrons is unequal.

Different types of an ion

Two conditions of inequality of charges between sub-particles of an atom are mentioned. Depending upon these two conditions we can categorize an ion into two different types either positive ion (cation) or negative ion(Anion).

What is a cation?

According to the first condition, when the number of protons is greater than the number of the electron in an atom, then the atomic structure is knowns to be positively charged. Such positively charged atoms are known as cations or positively charged ions. The charge on a cation depends upon the tendency of an atom to lose electrons from the shell. If one electron is removed then the charge is +1, if two electrons are removed from the shell then the cationic charge is +2 as illustrated in the given below example.

• It has been seen that the formation of cation is an endothermic reaction.

What does mean by term Endothermic?

The word endothermic means heat absorbing. Endothermic reactions or processes are those in which there is a need for absorption of heat to carry out the reaction.

Why it is an endothermic reaction let’s allow me to explain:

• Cation is formed when an isolated atom loses one or more electrons from its valance shell. As we know that there is the existence of a strong force of attraction in an atom. Due to this force of attraction nucleus strongly attract the valance electron, to remove an electron from a strong grip of the nucleus a sufficient amount of energy is required. This sufficient amount of energy is given to the electron which energies it and helps it to kick off from the strong field of the nucleus. As soon as the electron removes from the nucleus field it left behind a positive charge. Which is named cation. That’s why the formation of cations is an endothermic process.

Ionization energy:

The amount of energy that is required to pull out an electron from the valance shell of an atom is named ionization energy. An example is given below to illustrate the above statement:

Here 496 KJ/mole energy is required to form positive cation sodium from an isolated sodium atom.

• If we compare a cation with a parent atom by their size we concluded that A Cation is smaller than the parent atom. Why does this so happen?

When a positive cation is formed then the number of protons increases as compared to the number of electrons. As one or more electron are removed from the valance shell, there is the removal of the shell from an atom result in an increase in the nuclear pull on the remaining valance electron. That’s why the cation is less than the parent atom by its size.

How does a cation Represent symbolically and what charge does it constitute?

• It possesses a positive charge and suffix (ium) is used for cation. Such as Hydronium (H+)

What is Anion?

• Secondly when an atom has more electrons than the number of protons then the charged atom is referred to as an Anion or negatively charged ion. In other words, we can also say that an anion is formed when an isolated atom gains an electron.
• It has been seen that the formation of anion is an exothermic process.

What is meant by the word Exothermic?

An exothermic process is a process that occurs with the liberation of heat or energy. An anion or negatively charged ion is formed when an extra electron is gained by an isolated atom, this addition of extra electrons increases the energy of the atom resulting in instability of an atom. To attain stability, as the atom earlier it loses energy in form of heat. Thus the formation of uni-negatively ion is an exothermic process. Given below there is an example mentioned to explain the above statement:

Here when an electron is added to an isolated atom of chlorine, an amount of energy 349 KJ/mole is liberated. Which makes the reaction exothermic reaction.

• Size of an anion is always greater than the parent atom. As we see that during the formation of an anion one or more electrons are added to the atom. This extra addition of electrons increases the electron-electron repulsion in the valance shell of an atom which results in an extension of the electronic cloud. Due to an increase in some electrons in the outermost shell, the pull of nuclear on valance electron also Decreases. That’s why the size of an anion is always greater than the parent atom.

How does a cation Represent symbolically and what charge does it constitute?

It possesses a negative charge and the suffix (ide) is used for monoatomic anion and (ate) for the polyatomic anion. Such as hydride and hydrate.

Ionic bond and ionic compound:

As there is two type of charged ions one is a positively charged cation and the other is a negatively charged anion, due to their opposite polarity an electrostatic force of attraction arises between them. This electrostatic force worked as a driving force in the formation of an ionic bond. When two charges formed an ionic bond then a compound is formed which is named an ionic compound.

Classification of Ions:

Depending upon the type of atom from which an ion is formed we can classify it as a monoatomic, diatomic, or polyatomic ion.

Mono-atomic ion:

If an ion is formed from one type of atom it is referred to as a monoatomic ion. Examples of monoatomic cation and anion are;

• Aluminum cation is represented by the empirical formula Al?³.
• Proton is a commonly known caption of the hydrogen atom. This hydrogen caption is denoted by H ?¹
• Another example of a mono-atomic ion is manganese cation which is represented by the formula Mn ?². It also can form Mn ?³ and Mn ?4.

Illustration of monoatomic anion:

• Common example of a uni-negative ion is the fluoride ion which is represented by Fl ?¹.
• Along with this other examples are chloride ion, bromide ion, iodide ion, sulfide ion represented by chemical formula Cl?¹,

Br? ¹, I ?¹, S ?². As these belong to the 7th group, to complete their outermost shell they always prefer to gain an electron to form an anion.

Di-atomic ion:

If from two types of atoms an ion is made then it is referred to as a diatomic ion. An example of a diatomic ion is an Oxide ion denoted by the chemical formula O? ².

Polyatomic ion:

When an ion is made from more than one type of atom then it is referred to as a polyatomic or molecular ion.

Illustration of polyatomic cation:

Here below there are some common examples are provided;

• H3O? is the chemical formula of hydronium cation.
• Hg2?² is a mercurous cation.
• NH?4 is the chemical formula of ammonium cation.

Illustration of polyatomic anion

• A nitrate ion is a common example of a polyatomic anion. It is represented by the chemical formula NO3?.
• Cr2O3? is the chemical formula of chromium oxide anion.
• Another example of a polyatomic anion is the Sulfate ion which is represented by the chemical formula SO4?².

Ways one can create an ion;

There are several techniques one can use to create an ion. Here I explain two methods;

• Spontaneous collision
• Chemical interaction

Spontaneous collision:

• We can create an ion from a spontaneous collision. Byword spontaneous means an event occurs without any apparent external cause. Collision is a process in which two bodies violently interact with each other. Through spontaneous collision among molecules of the liquid, an electron or group of electrons may be knocked off from an atom resulting in the formation of an ion. This ion is positively charged. Along with a positively charged ion, a free electron is also formed. This type of ionization is commonly named physical ionization. The free-electron that comes into the process during the collision may stick to itself or another atom resulting in the formation of a negatively charged ion.

Chemical interaction

• One can create an electron through another process which is commonly known as “ chemical interaction”. For example when we dissolve an ionic compound in any form of a solvent such as water. The atom that comprises salt undergoes the process of separation to form a negatively charged anion & positively charged cation. A common example one can see to understand this process is the dissolving of common salt (sodium chloride) in water. When sodium chloride is dissolved in water then NaCl disassociates into positive sodium cation and negative chlorine anion.

Here Na+ represent positive cation ionic specie. And Cl- represent anionic specie.

• Another process that can be carried out for the formation of ions is the passage of direct current from a dissolved solution which can conduct. As the current is passed through the solution the liquid molecules break and positive and negative ions are formed.

That’s All today. In this article, we learn about ion, its type, and the representation of charges on the ion. I try to explain aspects that make cation and anion quite different from each other. And in last we studied techniques which normally used to create an ion. I hope the given material for the term “Ion” is helpful for your academic requirement. If you have any queries regarding this article. Mention your question in the comment session. In the next tutorial, we will learn about molecular ions. Our platform tries its best to satisfy you. Keep tuned.

Introduction to Atoms

Hello, friends today we will discuss the basic concept of chemistry it is our first tutorial series in which we will discuss:

1. Atom
2. Molecule
3. Ion
4. Molecular ion

Now in this article, we will discuss atoms. Its definitions, examples, properties, its evolutionary history, and also some important facts in the form of questions.

Atom

Definitions

A tiny particle that cannot be seen with a naked eye so-called atom.

Or

Atom is the lowest unit of matter and is often divided without the discharge of electrically charged particles.

Or

Atom is the introductory structure block of chemistry.

Examples

From molecule;

Hydrogen (H₂)

• It has two atoms.

Nitrogen (N₃)

• It has three atoms

From elements;

Helium(He)

• It has two electron

Properties

We discuss different properties of atoms like:

Atomic no:

The no of protons present in the nucleus of an element is called atomic number Or nuclear charge no.

. Its symbol is Z.

• Always a whole no
• No effect of neurons on atomic no.
• Always give a smaller value than atomic mass.

Examples

1. Carbon has 6 protons in its nucleus so its atomic no is Z=6
2. Sodium has 11 protons .so Z= 11

Atomic mass

The sum of the numbers of neutrons and protons in the nucleus of an atom is called atomic mass or mass no.

• It is represented by A and calculated as A=Z+n
• Where n is no of neutrons and Z is no of protons
• It always is greater than atomic no.
• It is affected by the addition of neutrons.

Example

Sodium has 11 electrons = 11 protons and 12 neutrons in an atom. So its mass no is

A= 11+12= 23

Periodic table

In this table, we can see atomic numbers, atomic mass, and symbols of atoms. Above the symbol is atomic no and below is the atomic mass.

Atomic size.

• We can not measure the size of an atom because atoms have no boundaries and they are very tiny, so can assume spherically
• It decreases if the atomic no is decreased from left to right in a period.
• In groups, atomic size gradually increases from top to bottom.

Atomic radius

The distance between the nucleus and the outermost orbit of the electrons of an atom is called atomic radius or atomic radii.

Relative atomic mass

The relative mass unit or atomic weight open element is defined as the number of atoms of an element in grams contained in 12 grams of carbon _12(isotope)

Atomic mass unit

The atomic mass unit or Dalton is defined as the one-twelfth of the mass of a carbon atom.

• It is also called Dalton.
• Its symbol is amu.

Interactions between atoms ( bonds)

Types of bonds

• Ionic bond
• Covalent bond
• Dative covalent bond
• Metallic bond

Ionic bond:

This type of bond is formed by the complete transfer of an electron from one atom to another.

Example

• Only valence electrons( electrons in the last shell) can take part in ionic bonding while others are not.
• In ionic bond formation, heat is released.

Covalent bond:

In this type of bond, electrons are mutually shared between two atoms.

Types

1. Single covalent bond
2. Double covalent bond
3. Triple covalent bond
4. Metallic bond

Single e covalent bond:

In which one bond pair of electrons is formed by the contribution of an electron by each bonded atom.

• Indicated by a single line

Double covalent bond:

In which two bond pair is formed by the contribution of electron pair from each atom.

• Indicated by double lines

Triple covalent bond:

In which three bond pairs are formed by the contributions of three electrons from each bonded atom.

• It is indicated by three lines.
• Each bonded atom attains octet by sharing of bond pair of electrons and attaining the nearest noble gas configuration.

Dative covalent or coordinate covalent bond:

A bond is formed between the electron pair donor and the electron pair acceptor.

• The atom which invests a pair of electrons is called a donator.
• The atom that receives that electron pair is called the acceptor.
• Those valence electrons that are not taking part in bonding and available on an atom like the one available on nitrogen in ammonia.

Example:

Polar covalent bond:

Those covalent bonds in which hetero atom takes part and one attracts the bond pair of an electron more strongly than the other.

None polar covalent bond:

If a covalent bond is constituted in which two similar atoms shared pair of the electron is excited by the both equally. such a type of bond is called a nonpolar covalent bond.

Predominantly covalent:

If the electronegativity between two elements is more than 1.7 the bond between them will be predominantly ionic and if it is less than 1.7 the bond between two atoms will be predominantly covalent.

Metallic bond:

A metallic bond is formed due to free electrons.

Evolutionary history of the atom

Timeline: 400 BC.

Scientist: Democritus

Theory of universe:

A first-person who uses the term atom(mean individual derived from atoms) was a Greek philosopher. He says that if you divided a piece of matter and divide and continue dividing, at any moment reach when you can’t divide it more, that fundamental unit was Democritus called an atom.

• Atom is made from matter and can not be seen by the necked eye.
• Between atoms, there is a space.
• Atoms are in the form of a solid-state.
• There is no internal structure in an atom.
• Every atom has a different shape, size, and weight.

Timeline:1800s

Scientist: Jhon Dalton

• The first person presents an atomic model of the behavior of the theory of the behavior of atoms consisting of small particles.
• Atoms cannot change their shape and are indestructible.
• By the weight of atoms, their elements can be characterized.

• Atoms combined to firm a compound.

Timeline: 1890s.

Scientist: Thomson

J.JThomson was a physicist who use cathode ray tube technology to discover electrons.

• In this tube, the air has been sucked out.
• An electric charge travels from cathode to anode
• Florescent gas light up the whole tube and the charge in it is invisible. When a charge hits the beam, a dot will appear on the screen.
• A beam of light travel in a straight line in a fluorescent tube.

• Each coil has a specific charge on a deflection.
• From a negative coil, the charge would defect away as Thomson shows.
• So he formed that charge this a negative charge.

When he found that negative charge, he did not stop and did a series of experiments, he discover the mass of the electron. He found that the mass of an electron is 1000 times lighter than a hydrogen atom. He made a statement saying that an electron must be inside an atom. Before it, he says the negative charge corpuscles later his name was changed and named as an electron.

Thomson’s atomic model

Using her prediction, he discovered what an atom looks like?

• His model was named plum pudding model his name.
• Each atom has a spherical shape and is inserted with positively charged fluid. He says it sticky jam part of a pudding.
• In this fluid, corpuscles (electrons) are the negatively charged particles suspended. He compared it to plum in the pudding.
• The movement of these electrons is not discovered by Thomson.

Timeline: 1910’s.

Scientist: Ernest Rutherford

Sir Rutherford made a famous gold foil experiment and proved the Thomson atomic model.

• He fired positively charged alpha particles at a gold foil.
• He estimated the deflection came out the other side.
• Every particle has not been deflected. Every particle would deflect back in all the ways.
• He assumed that the center of the foil must be positive. He called his nucleus.

Rutherford's Atomic model

• The nucleus consists of positively charged particles.
• The electrons revolve around the nucleus.
• He faces one problem: Why nucleus can’t attract the electrons?

• He compared the atom with a mini solar system in which electrons revolve around the nucleus in a fixed orbit due to this he called his planetary model

Timeline:1910’s

Scientist: Neils Bohr

Niels obeys the planetary model but he found some disadvantages. He could answer the Rutherford question

Why electrons do not fall into the nucleus?

He replies with a perfect answer to the question because of his knowledge of quantum physics and energy.

Bohr's atomic model:

• Electrons have fixed energy and size in orbits of the nucleus.
• The energy of an electron depends on the orbit in which the electron revolves.
• Electrons fill the lower orbit first.
• If the first energy level(orbit) is filled then the next will began to fill.
• When an electron moves from one orbit to another, the radiation process occurs.

There is a problem with this theory: Electrons could not move in a specific path or orbit.

Timeline:1920’s

Scientist: Erwin Schrodinger

He was a revolutionary physicist and he presented the atomic model by using Heisenberg’s uncertainty principle.

Schrodinger’s atomic model(Aka the cloud model)

• An electron would not revolve in a fixed orbit.
• We can find out where it likely is.
• Energy level depends upon the type of probability of orbit described by Bohr.

Facts

What is not an atom?

By the definition, atoms are the units of matter, so those are not atoms that do not consist of matter.

Parts of atoms that are not associated with a proton are not atoms.

An electron is not an atom, also neutrons bonded to other neutron is not an atom.

Why does an atom react?

Atoms react for attaining the nearest noble gas configuration and become more stable by following the duplet or octet rule.

Why the shape of the atom is spherical?

We can say that an atom “has the shape of the sphere” because a positively charged nucleus is at the very center, and the negatively charged electrons are distributed around it. The electrons are attracted to the nucleus and repel each other. A nucleus, the mass of neutrons and protons within an atom, arranged itself in a roughly spherical shape.

Why the revolving electron does not fall into the nucleus?

Electrons revolve in fixed energy levels around the nucleus. It can not befall into the nucleus because electrons do not radiate energy and move in a circular orbit due to necessary centripetal force.

Why neutrons are neutral and do they exist in the nucleus?

We have an idea from its name, the neutron is the neutron. In other words, the interaction between protons and electrons can cause the formation and destorarion of neutrons. As electrons are negatively charged and protons are positively charged particles. So they cancel each other charge and that’s why neutrons carry no charge and they are neutral. They exist in the nucleus for the stability of nuclei.

Why carbon 12 is used in the references of all atomic mass units?

At the start, hydrogen is used to measure but it gives a fraction. so it would be changed into oxygen, Scientists used a mixture of natural oxygen but it led to confusion. So again changed the reference and turned it into carbon – 12. We use this because it gives all the atomic mass units in exact no. The reason is the different ratio of the mass of proton and neutron performing the change of nuclei.

I Hope, I cover all aspects of the atom, in the next tutorial we will learn about the molecules. If someone has any questions about the atom I will try to answer them. write it in the comment box. Thanks

Introduction to Organic Chemistry

In this article, we will discuss the introduction to organic chemistry in which we will study organic compounds, classification of organic compounds, types of formulas, use, significances, general and covalent bond characteristics of organic compounds, and homologous series and his characteristics. 9 out of 10 takes the organic chemistry too tough but I explained it easily and simply to you. This article is for beginners and clears many topics.

Introduction to organic chemistry

Old Definition:

“The chemistry of compounds obtained from living things.”

Vital force theory

Swedish Chemist Jacob Berzelius put forward this theory in the 19th century.

State

“ Organic compounds could not be synthesized in the laboratory due to the influence of a mysterious force called vital force, which occurs only in living things.”

• This theory falls in 1828 when Wohler prepared urea by heating it from ammonium cyanate.

Equation

 

• Also in 1845 when Kolbe prepared acetic acid in the laboratory.

Advanced definition;

The branch of chemistry in which we study hydrocarbons and their derivatives is known as organic chemistry.

Organic Compound:

Organic compounds belong to hydrocarbons and their derivatives which are covalently bonded to carbon.

Examples

There are so many examples of organic compounds

• Carbohydrate
• Artificial fibers
• Fertilizers
• Plastics
• Paints
• Dyes
• Pharmaceutical products
• Lipids
• Enzymes etc.

Chart

Formulas of organic compounds:

Organic compounds had six types of formulae;

1. Molecular formula
2. Structural formula
3. Condensed formula
4. Dot and Cross formula
5. Empirical formula
6. Skeleton formula

Molecular formula:

The formula In which the exact no of atoms is mentioned in one molecule of the organic compound is called the molecular formula.

Examples

The molecular formula of methane CH_4.

• Methane is made up of one carbon atom and four hydrogen atoms.
• Each molecule of methane consists of one carbon atom and four hydrogen atoms.

Structural formula

The formula of organic compounds shows the actual arrangement of different atoms of various elements present in a molecule.

• The structural formula of organic compounds differs but may have the same molecular formula as propane
• A single bond represents a single line(__)and double bond show double lines (=) and a triple bond show three lines in a structural formula.

Example

The structural formula of propane is

Iso_ propane

Condensed formula

The formula in which groups of atoms are linked with each carbon atom in a branched-chain or straight chain.

Example

The condensed formula of propane

Iso_propane.                                                                                  n_propane

Electronic or Dot and Cross formula

The formula in which sharing of electrons in a dot and cross-form between the various atoms in one molecule is indicated is called electronic or Dot and Cross formula.

Example

Empirical formula

In which whole, no ratio of different atoms in a compound gives the empirical formula of organic compounds

Example

Skeletal formula

The essential form of structure of an organic compound makes a series of atoms that are bonded together in the form of a chain, branched, or rings called the skeleton formula.

Example

skeleton formula of propane is

Classification of organic compounds:

Depending upon their carbon atoms, organic compounds are divided into two categories.

1. Open chain or acyclic compounds
2. Closed chain or cyclic compounds

Open chain or Acyclic compounds:

Acyclic compounds form a long chain of carbon atoms without joining the end of the cross-format with each other. They may form straight or branched chain compounds

• Straight chain compounds
• Branched-chain compounds

Straight chain compounds

A straight-chain is formed by the linking of carbon atoms with another carbon atom or any other atoms through single, double, or triple bonds.

Example

propane

Branched-chain compounds

Open chain compounds i.e. aliphatic compounds in which a branch along with a straight chain is formed.

Closed chain or cyclic compounds

The carbon atoms of closed chain compounds are not free from their ends and it contains one or more close chains. These are divided into two groups

1. Homocyclic or carboxylic compounds
2. Heterocyclic compounds

Homocyclic or carbocyclic compounds

These compounds are made up of rings of carbon atoms. These are further divided into two groups.

1. Aromatic compounds
2. Alicyclic compounds

Aromatic compounds

Aromatic compounds consist of benzene rings at least one in their molecule. Six carbon atoms with three double bonds make a benzene ring, these compounds are also called benzenoid compounds. They have aroma or smell so they are also called aromatic compounds.

Example

Alicyclic compounds Or none_benzenoid compounds

These are called none_ benzenoid compounds because the benzene ring is not present in these compounds.

Example

Heterocyclic compounds

Those cyclic compounds that consist of one or more atoms other than that of carbon atoms in their rings are known as heterocyclic compounds.

Example

Chart

The classification of known compounds is as follows

so the organic compounds are open or closed chains. Open chains are further divided into alkane, alkene, and alkynes. Closed chains may be homocyclic or heterocyclic. Homocyclics are alicyclic or aromatics.

Major sources of organic compound

From plants and animals, organic compounds are naturally prepared.

From animals:

Protein and fats are the two major groups of organic compounds that are synthesized by animals.

• Protein included chicken, egg format and mutton, etc.
• In milk and butter fats are present.

From plants

Plants could be prepared

• Fats
• Vitamins
• Proteins
• Carbohydrates

From dead plants through a biochemical process, we obtain

1. Coal
2. Gas
3. Petroleum

By the destructive distillation of coal and petroleum, we obtain thousands of organic compounds.

Coal

A blackish, complex mixture of organic compounds of carbon, hydrogen, and oxygen is called Coal

In the absence of air, strong heating of coal is called Destructive distillation.

Distilled products of coal

Except for carbon, coal contains different elements like hydrogen, oxygen, sulfur, and nitrogen.

So huge number of organic compounds are formed due to the destructive distillation of coal with few inorganic compounds.

Products:

1. coal gas
2. coke
3. Coal tar
4. Aluminum liquor

Fractional distillation of coal

Coke

When coal is passed through the destructive distillation process. A solid residue left behind and lost all of its volatile elements is called coke.

Fractional distillation

The techniques, in which different ranges of temperature are used to separate the mixtures of the coal in terms of temperatures. we get different products at different ranges of temperature.

Uses of coal

• Used in the preparation of nitrogenous fertilizer.
• Used in roads and leveling of roads.
• In the extractions of metals, especially iron is used as a reducing agent.
• Used mainly in fuel.
• Used in plastics, synthetic fibers, and pesticides.

Chart

The below chart shows the uses and types of coal

Petroleum

A Greenish black or dark brownish colored viscous liquid is called petroleum.

It is a complex mixture of salt, water, and Earth particles mixed with a mixture of serve solid, liquid, or gaseous hydrocarbons.

As a Source of organic compounds

The main source of organic compounds is petroleum and it is separated through fractional distillation. Different organic compounds consist of each fraction of petroleum that is not a single compound.

Natural Gas

Natural gas consists of serial gases like 85% of methane, nitrogen gas, carbon dioxide, propane, butane, and ethane.

Uses

• Used in fertilizer
• Making carbon black
• Compressed natural gas (CNG) is used in automobiles.
• Use in different industries and as well as in homes.

Plants

Macromolecules are formed by living plants

• Oils
• Vitamins
• Proteins
• Carbohydrates

Use

• Gums
• Rubber
• Medicines

Prepare in laboratory

Two centuries ago, due to the vital force theory, we considered that organic compounds are prepared only from animals and plants and could not be synthesized in the laboratory.

But

A large amount of the organic compounds, almost more than ten million are synthesized in a laboratory.

• Wohler synthesis urea in laboratory
• Kolbe prepared Acetic acid
• Drugs and medicines
• Fragrance and flavors
• Pesticides and insecticides
• Synthetic rubber and fibers
• Plastic and paints.

Synthesized products in the laboratory from animals and plants

Urea

Urea opens the way for chemists to prepare organic compounds in the laboratory and it is synthesized by inorganic salts.

Example

The fermentation of barley and molasses produced alcohols.

Natural Rubber

Synthetic rubber has much more qualities than natural rubber-like

• Non-inflammable
• Resist high temperature
• No reaction between ozone and oxygen

Synthetic fibers

Different fibers are made in laboratory-like

• Nylon
• Rayon
• Polyester etc.

Natural fibers have better properties than synthetic fibers like

• The ability of low water absorption
• Greater strength
• Good elasticity

Drugs and medicines

All proteins, sweeteners, vitamins, drugs, and medicines are being prepared in laboratories.

Uses of organic compounds

There is no doubt that more than ten million compounds are made in the laboratory but thousands of organic compounds are naturally synthesized by plants and animals.

Use in food

We use different organic stuff daily such as milk, eggs, vegetables meat, etc. contain protein, vitamins, fats carbohydrates, etc.

Use in cloth

Natural fibers and synthetic fibers, all are organic compounds used in cloth making that we use daily for wearing bedsheets, etc.

Use in raw materials

A variety of organic compounds are used in raw materials such as

• Drugs
• Paper
• Ink
• Dyes
• Paints
• Pesticides
• Rubber etc.

Use in wood

cellulose naturally occurring organic compound in wood that is used for making furniture and housing.

Use in fuel

Coal, petroleum, and natural gas are all organic compounds called gospel fuel that is used for domestic purposes and automobiles.

Use in medicine

antibiotics (kill or inhabitants of microorganisms that cause infectious diseases) are life-saving medicines.

Characteristics

The general characteristics of Organic Compounds include:

• Can be separated as well as prepared in the laboratory
• Comprise almost 90% of all known compounds.
• Mostly accumulated of only three elements- carbon, hydrogen, and oxygen. Other elements like halogen and nitrogen besides phosphorous are also existing but to a small extent.
• Retain complex patterns and high molecular weights
• Their properties are determined by a specific active atom or group of atoms recognized as the functional group.
• They are primarily insoluble in water but soluble in organic solutions.
• They are flammable
• Chemical reactions comprising organic compounds continue at slower rates.

Characteristics due to Presence of Covalent Bonds

A covalent bond is a chemical bond that influences the sharing of electrons pairs between atoms in a switch resulting in a balance of impressive and despicable forces between the atoms. The presence of a covalent bond renders specific elements to the organic compounds. These include:

• Low melting points and boiling points.
• Organic acids and bases are powerful and thus they have a particular dissociation in an aqueous medium.
• They express the process of isomerism in which an isolated molecular formula characterizes several organic compounds varying in physical and chemical properties.
• They are flammable.

A major characteristic of Members of Homologous Series

A Homologous Series is a community of organic chemical compounds, usually summarized in the order of increasing size, that have an identical structure (and hence, also similar properties) and whose structures vary only by the number of CH2– CH2 units in the fundamental carbon chain.

They maintain the following general characteristics:

• A common formula defines the members of the homologous series.
• Succeeding members differ from each other by CH₂CH₂
• Physical properties change regularly with an increasing number of carbon atoms.
• Members have similar chemical properties because they have an identical functional group because can be assembled using the same method.

Significance of Organic Compounds

• Organic compounds are important because all inhabiting organic compounds contain carbon.
• While carbohydrates, fats, the basic structures of life, are organic compounds
• They are the basic units of many of the cycles that move the earth. For instance, the carbon cycle comprises the deal of carbon between plants and animals in photosynthesis and cellular respiration.
• Organic compounds get together with metals to form organometallic compounds. These compounds are valuable industrially. They are employed as catalysts, promoters, analyzers as well as stabilizers.

So this is all for our today's article. I have tried my best to explain all the important topics covered in the heading " Introduction to Organic Chemistry". So if you want more tough articles in simple ways then give me good feedback. It will help me for better work. Thanks

What is Stoichiometry? How it helps in Balancing Reactions?

The topic we are going to discuss today can be crowned as the most celebrated concepts in the field of Chemistry, the most celebrated amongst the chemists yet most hated amongst the students due to its complexity, who loves balancing chemical equations? Definitely no one! So cutting it short we are here to discuss " Stoichiometry ". The very first time I encountered this word years ago it felt like a tongue twister to me, let's learn to pronounce it first, stoichiometry is pronounced as "stoy- key-om-Et-tree", you would definitely learn to pronounce it well by the end of this discussion, keep trying! So, let's get started with Stoichiometry:

What is Stoichiometry?

• In a chemical reaction, different reactants react together in different quantities and generate products.
• For example, in the below chemical reaction, Hydrogen & Oxygen are reactants and they are producing water as a result of an exothermic reaction:

• As you can see in the above reaction,
  • Reactants: 2 atoms of hydrogen + 2 atoms of oxygen
  • Product: 2 atoms of hydrogen + 1 atom of oxygen.
• So clearly, there's a molecular difference between reactants & products and according to the Law of Conversation of mass:

"Mass of a system(chemical reaction) remains constant over time, if no energy enters or leaves the system."

• In simple words, the molecular mass of reactants must be equal to that of products and if it's not the case, then such reactions are called UnBalanced Reactions.

UnBalanced Reactions

• Unbalanced Reactions are also called Skeletal Reactions and provide information only about the type of ingredients & Products used in a chemical reaction.
• It doesn't give any information about the quantity of the reactants or the products.

Balanced Reactions

• A chemical reaction, which strictly follows the law of conservation of mass i.e. the molecular mass of reactants must be equal to that of products is called Balanced Reaction.
• For balancing a chemical reaction, numerical coefficients are used and are placed on the left side of the entity.
• Now let's balance the above unbalaced reaction to understand it completely, balanced reaction is shown in the below figure:

• As you can see in the above figure, I have used Numerical values called Coefficients to balance the equation.
• Now, in this balanced reaction, we have an equal number of atoms in reactants and products, i.e.:
  • Reactants: 4 atoms of Hydrogen + 2 atoms of Oxygen.
  • Products: 4 atoms of Hydrogen + 2 atoms of Oxygen.
• These coefficients are simply multiplied by the number of atoms.
• This technique of balancing a chemical reaction is called Stoichiometry.

Advantages of Balancing a Chemical Reaction

• As we have seen in the above water reaction, once we have balanced the reaction, it got clear that we need 2 moles(molecules) of Hydrogen and 1 mole(molecule) of oxygen, if we want to produce 2 moles(molecules) of water.
• So, with the help of a balanced equation, a scientist can easily calculate the number of ingredients for producing a certain amount of product.

Now let's have a look at a proper definition of Stoichiometry:

Stoichiometry Definition

• Stoichiometry is a set of mathematical techniques, used for determining a quantitative relationship between reactants and products in a chemical equation/reaction.
• The term stoichiometry has been derived from the two Greek words, the first one is “Stiochos” which means elements and the second one is “metry” which means measuring, so the word collectively means "Measuring Elements".
• It was coined by Jeremias Benjamin in 1972, in the first volume of his book Richter's Stoichiometry also known as the Art of Measuring the Chemical Elements.

Stoichiometric Coefficients:

• Coefficients are the whole numbers, written in front of the elemental symbols in the equation, indicating the number of moles or the number of molecules.
• If there is no coefficient in front of a symbol, then 1 is assumed to be the coefficient.

Now let's have a look at why do we need Stoichiometry in chemistry:

Why do we need stoichiometry?

• We need stoichiometry for two reasons, mentioned as follows:
  1. For balancing a chemical reaction.
  2. For conversions i.e. grams to moles & moles to grams.

Let's understand both of them in detail:

Balancing a Chemical Reaction

• There are no fixed rules for balancing a chemical reaction, it depends more on your analytical skills, but there are few tricks.
• While balancing a chemical reaction, always balance individual elements one by one, as in a water reaction, we first balanced oxygen and then hydrogen.
• First balance that element, which has the least occurrences in the reaction, as for water oxygen atoms appeared 3 times, while hydrogen atoms were 4 times.
• Try to balance single elements first, as balancing elements from a compound is bit difficult.
• But again as I said earlier, these are few tricks to ease the process, but it mainly depends on analytical skills and practice.
• Your equation is said to be balanced when it will have an equal number of atoms on both sides i.e. obeying the Law of conservation of mass.
• So, let's balance few reactions to understand How it works:

Stoichiometry Example1: Water Reaction

• I have already shown both unbalanced & balanced equations of water but now let's have a look at the steps taken to balance it.
• So, we have an unbalanced equation as shown in the below figure:

• As you can see in the above figure, we have an unbalanced equation, so we need to analyze, which element can be balanced easily.
• Clearly, we are using 2 atoms of oxygen in reactants but the product contains only 1 atom.
• So, we need to multiply the product by 2 so that, we could balance oxygen items, as shown in the below figure:

• We have balanced oxygen items in the above equation, but now in reactants, we are using 2 hydrogen atoms but in the product, we have 4 atoms.
• So, in order to balance hydrogen atoms, we need to multiply hydrogen reactant with 2 as well, as shown in the below figure:

• Now we have an equal number of atoms(of both hydrogen & oxygen) in reactants and product and we can say, we have a balanced equation now.
• So, if we want to produce 2 moles of water(36g molar mass), then we have to combine 2 moles of hydrogen(4g) and 1 mole of oxygen(32g).

Now let's have a look at another example:

Stoichiometry Example 2: Propane Reacts with Oxygen

• Now, lets have a look at another reaction, where Propane reacts with oxygen and generates carbon dioxide and water, as shown in the below figure:

• As you can see in the Stoichiometry example, I have followed the above mentioned tricks.
• First of all, the point to notice is I have solved all elements individually, first Carbon, then Hydrogen and finally Oxygen.
• Moreover, I have Carbon first because it has appeared in two entities and was quite easy to balance.
• And in the last step, we got our balanced equation having an equal number of atoms on both sides of the reaction.

Stoichiometry Example 3

• Here's a quick example to show you that in complex equations, we may have to re-evaluate our coefficients, as shown in the below figure:

I hope you guys have completely understood the concept of balancing a chemical reaction. Always remember, whenever you are going to solve a stoichiometric numerical problem, you have to balance the chemical equation first, otherwise you won't be able to solve the problem correctly. It is a necessary evil! Don't skip it, okay? Now let's have a look at How to perform conversions from one unit to another using balanced equations.

Unit Conversions using Stoichiometry

In the previous section, we have seen How to balance a chemical reaction and now we will discuss How to make unit conversions of chemical elements using these balanced equations.

• Normally, the quantity of a chemical substance is measured using two different units, which are:
  1. Moles.
  2. Grams.

Moles Definition

• Mole is the SI unit for quantity/amount of a chemical substance and 1 mole of any substance contains 6.02 × 10²³(Avogadro's no) atoms of that chemical substance.
• The term molecules and moles are used interchangeably, and if you ask me, mole is just the short form of the molecule.
• So generally, the number of molecules of a chemical substance, used in a chemical reaction is denoted by the unit called Mole(denoted as mol).
• As you can see in the below water reaction, 2 moles of Hydrogen are reacting with 1 mole of oxygen and producing 2 moles of water.

Now let's have a look at the grams definition:

Grams Defnition

• When chemical substances are measured using their molar/molecular mass, then the Grams unit is used, denoted by g.
• Molar mass can be defined as the mass of one mole of a substance in grams.”
• Again let's understand it with water reaction:

• So, in the above reaction, I have displayed both moles and grams, so if you want to use the grams unit then we can say that:
• 4g of hydrogen is reacting with 32g of Oxygen and producing 36g of water.
• You must have noticed that we have an equal number of mass(in grams) on both sides of the equation as the balanced equation must obey Law of conservation of mass.

Moles Vs Grams

The following table shows the difference between Moles & Grams:

ESP32 Module Features and Technical Specs
No.	Mole(mol)	Grams(g)
1	The Mole unit is used to count the number of entities(chemical substances) used.	Gram unit is used to measure the amount(molar mass) of chemical substance i.e. how much quantity is used?
2	Moles are normally integers	mass in grams could be a fraction.
3	Total moles of reactants may or may not be equal to that of products in a balanced chemical reaction.	The total mass(in grams) of reactants must be equal to that of products in a balanced chemical reaction.
4	Mole unit is used in theory mostly.

Molar Ratio

• As we have seen, Stoichiometry is the knowledge of balancing the chemical equations.
• These chemical reactions are actually giving us the ratio between reactants and products.
• Let's understand this ratio with water reaction:

• So, in water reaction, we have a ratio of 2:1:2 between Hydrogen, oxygen and water respectively.
• As this ratio is between moles of the reactants and products, thus it's called the Molar ratio.

Now let's have a look at How to make conversions between moles and grams using the molar ratio.

Conversions between Grams & Moles

There are four types of conversions that can be performed between these two units in stoichiometry, which are:

• Moles-Moles Conversion
• Grams-Moles Conversion
• Grams-Grams Conversion
• Moles-Grams Conversion

Grams-Grams Conversion is the most widely used one. Now let's solve few Stoichiometry problems to understand these conversions. These real-life problems will also help you understand the importance of stoichiometry calculations and how they are used in chemistry.

Stoichiometry Problems

In stoichiometry we come across a number of numerical problems that ask for the following calculations;

• Finding out the limiting reactant of a reaction.
• Calculating the actual yield of a reaction.
• Theoretical yield of a chemical reaction.
• Finding out the empirical formula of a compound after combustion analysis.

All these calculations are stoichiometric in nature as it involves the above-mentioned conversions. In this discussion, we are going to pick one problem from each of the above topics and I would help you solve and understand them in the best possible way. Let's get started!

Find Limiting Reactant using Stoichiometry

Limiting reactant can be defined as:

• A limiting reactant(also called a limiting agent) is a chemical substance/element, that takes part in a chemical reaction in a limited amount & controls the amount of product produced.

Many times, we are asked to identify the limiting reactant in a numerical problem, following is one of such problems:

Stoichiometry Problem Statement:

During a chemical reaction 3.2 moles of N₂ react with 5.4 moles of H₂ to form NH₃, how much amount of NH₃ can be formed in the process? Which one is the limiting reactant? How of the excess reactant would be left over after the consumption of the limiting reactant? Solution:

Step 1: Write the Balanced Equation of the chemical reaction:

• We will start by writing the balanced chemical equation for the above reaction

N₂ (g) + 3H₂ (g) ? 2NH₃ (g)

Step 2: Determine the Limiting Reactant b/w N₂ & H₂

• We will now determine the amount of N₂ consumed by H₂.
• So, from above balanced equation, we have the molar ratio of 1:3:2 between nitrogen, hydrogen and ammonia respectively.
• So, we can find the limiting reactant as shown in the below figure:

• As, we can see in the above calculations that 9.6 mol of H₂ Is required to fully consume 3.2 mol of N₂, but in the statement, we are only provided with 5.4 mol of H₂, so clearly H₂ is our limiting reactant here.
• Now, we will be calculating the total amount of N₂ consumed with the provided 5.4 mol of H₂, so:

3 mol of H₂ consumes = 1 mol of N₂

1 mol of H₂ consumes = 1/3 mol of N₂

5.4 mol of H₂ consumes = 5.4 × 1 / 3 mol of N₂ = 1.8 mol of N₂.

Step 3: Determine maximum product produced by the limiting reactant

• Next, we need to find the amount of product, that we can produce using these reactants.
• As we already know that H₂ is our limiting reactant, so simply we need to apply the molar ratio between H₂ and NH₃.
• For this, we can do the following calculation:

3 mol of H₂ produces = 2 mol of NH₃

1 mol of H₂ will produce = 2/3 mol of NH₃

5.4 mol of H₂ will produce = 5.4 × 2 / 3 mol of NH₃ = 3.6 mol of NH₃

• So, 3.6 mol of ammonia is the maximum amount, that can be produced with the number of reactants given in the problem statement.

Step 4: Determine the amount of excess reactant

• If you want to determine the amount of N₂ still left after the reaction, there is a simple formula for that i.e. number of moles given - number of moles used = amount of excess reactant left
• 3.2 mol - 1.8 mol = 1.4 mol of N₂ are left after the consumption of the limiting reactant.

Step 5: Conclude the results

The conclusion can be written as;

• H₂ is the limiting reactant
• N₂ is the excess reactant, so only 1.8 mol will be consumed and 1.4 mol will be left.
• 3.6 mol of NH₃ can be produced with the reaction of 5.4 mol of H₂ and 1.8 mol of N₂.

Calculating Actual Yield and Theoretical Yield

First, let's have a look at their definitions:

Yield Definition

• It is the amount of product formed during a chemical reaction.

Theoretical Yield

• The amount of stoichiometric product calculated on paper without any practical experimentation, we can also regard it as an estimated product.

Experimental/Actual Yield

• The actual amount of product formed during a chemical reaction on practical grounds.

Practical yield can be equal or less than the theoretical yield, most of the students ask why and how it happens? Here is a simple answer:

• We don't have ideal conditions of temperature and pressure in the industry
• There is a loss of reactants in the process of transferring, mixing etc.
• Mechanical losses are always there which can never be ignored.
• An impure reactant can add to the agony of the procurement team as well

Percentage yield

• Percentage yield is the percentage ratio of actual/experiment yield to the theoretical yield.
• It can be mathematically written as:

% yield = actual yield / theoretical yield × 100

Why we use this concept? You must be thinking why we need this simple percentage in our lives, let me tell you why! It is extremely crucial to industries either chemical or pharmaceutical, they calculate the amount of profit or loss through this method. You might have faced the discontinuation of your favorite soap or shampoo or bubble gum in your life, it was all due to the decrease in the %age yield of the product that was not good enough to continue because when a product has a lesser profit margin there is no other choice than to discontinue it! Production is highly dependent on this concept regarding it to be a success factor for a product to rule the market. It’s time for a numerical problem to help you better understand the concept!

PROBLEM STATEMENT

42 grams of hydrogen reacts with nitrogen to form 120g of ammonia, determine the percentage yield of the product formed during the reaction.

Step1: Write the balanced chemical equation

N₂ (g) + 3H₂ (g) ? 2NH₃ (g)

 

Step 2: Convert grams into moles

• As the quantities are given in grams, so we need to convert them to moles first. So,

Moles of H₂= mass in grams / molar mass

= 42/2 = 21 moles

 

Step 3: Calculate NH3 Theoretical Yield

• Next, we need to calculate the moles of the product by comparing it with the reactant using a balanced chemical equation.
• So, the molar ratio between H₂ & NH₃ is 3:2, so:

3 mol of H₂ produces = 2 mol of NH₃

1 mol of H₂ will produce = 2/3 mol of NH₃

21 mol of H₂ will produce = 21 x 2/3 mol of NH₃ = 14 mol of NH₃

Convert moles into grams because the actual yield has been given in grams and units of two quantities to be compared must be the same.

Mass in gram of NH₃= number of mole × molar mass = 14 × 17= 238g

Step 4: Calculate Percentage Yield

• Now, calculate the percentage yield by putting the values into the given formula:

Actual yield of NH3 = 120 grams

% yield = actual yield ÷ theoretical yield × 100 

= 120 / 238 × 100

            = 50.5% is the calculated percentage yield of NH3

This is how we calculate the %age yield of a chemical reaction.

Calculating Empirical formula with Stoichiometry

As we are well aware of combustion, how and why it happens, it's time to solve the stoichiometric problems related to combustion analysis in which students are mostly asked to find empirical formulas. The empirical formula is different from the molecular formula, don't confuse both with each other here's why! “Empirical formula can be defined as the simplest ratio of atoms or elements present in a compound” Example: The molecular formula of benzene is C6H6 meanwhile the empirical formula is CH. Features of Empirical Formula:

• Contains the most simplified ratio of the moles of elements making a compound
• It is simply a ratio, not an exact number or amount of atoms or molecules making a compound.
• Determined by weight percentages by converting them into grams.
• It is not commonly used in experimental schemes as compared to molecular formulas.

Features of Molecular Formula:

• It is the actual number of atoms or molecules forming the compound
• We calculate it after the calculation of the empirical formula
• It is a by-weight representation of every constituent particle making the molecule.
• It is commonly used in chemical reactions and stoichiometric calculations
• The molecular formula is always a multiple of the empirical formula; we can calculate empirical formula by a simple calculation at glance.

NUMERICAL PROBLEM

• A compound is composed of 52.14% of carbon, 34.7% oxygen and 13.13% of hydrogen by mass. Given that the molar mass of the compound is 138.204 g/ mole, Calculate The empirical formula and molecular formula.

Step 1: Convert percentages into grams

• Carbon = 52.14g
• Hydrogen =13.13g
• Oxygen=34.7g

Step 2: Convert grams into moles

• For carbon:

no of moles = mass in grams/ molar mass

52.14 = mole / 12 g per mole = 4.34 moles

• For hydrogen:

no of moles = mass in grams / molar mass = 13.13 / 1 = 13.02 moles

• For oxygen:

no of moles = mass in grams / molar mass = 34.73/ 16 = 2.17 moles

 

Step 3: Dividing with a common denominator

• Divide the number of moles of all 3 atoms with the lowest number of moles obtained:

Number of moles for Carbon =4.34 moles/ 2.17= 2

Number of moles of hydrogen= 13.13/2.17=6

Number of moles of oxygen = 2.17/2.17 =1

Step 4: Setup your Empirical formula

• C₂H₆O is our empirical formula

Step 5: Calculate the molecular formula

• Add up and calculate the atomic mass of each element

2C + 6 H + O

= 2×12 + 6× 1.008 + 16 = 46.08

Molar mass/mass in grams = 138/46 = 3

Multiply 3 with the empirical formula subscripts

So the molecular formula is C₆H₁₈O₃

  This is how we calculate the empirical formula, summarizing it;

• Convert %age into grams
• Then convert grams into moles afterward
• Divide the moles with the least amount of moles obtained
• The digit obtained is the empirical formula!

Summing up, stoichiometry is hard to understand at first but practice can make it easier for you, have patience and don't fret, learn the formulas by heart and efficiently rearrange them to extract the desired entity which is missing! See you soon with the next topic, good day!

Periodic Table of Elements: Definition, Groups & Trends

Hello friends, I hope you all are doing great. In today's tutorial, we will have a look at a detailed overview of Periodic Table. Understanding the Periodic Table is one of the nightmares everyone had once in a lifetime, don't fret! I was one of those people too. Today I would be breaking down this complex topic into smaller digestible chunks. Before diving deep into the topic let me introduce you to the fact that atomic number is more reliable than the atomic mass of an element, every element has a fixed atomic number and it increases by a value of 1 with every element in the modern periodic table, that is the reason why we use Atomic Number instead of Atomic Mass as the base of the modern periodic table.

History of Periodic Table

Rome wasn't built in a day, in the same way, the modern periodic table isn't the product of a single effort from a chemist or two, it took two centuries to complete. The older version of periodic table was based on Atomic Masses by Dimitri Mendeleev, Many scientists contributed to the formation of the periodic table such as:

• Doberiner presented the idea of Triads when he observed the relationship between the atomic masses of three elements. Within a Triad the central element had the atomic mass equal to the average of two corresponding elements.

• Newlands proposed the Law of Octaves in 1864 when he observed the repetition of properties in every eighth element, when elements were arranged in an order of increasing atomic masses.

Later on, after the discovery of atomic numbers by Henry Mosley in 1913 and some new elements modern periodic table is now based on the increasing order of atomic numbers which was proposed by Henry himself when he discovered atomic numbers. Let's have a look at the proper definition of periodic table:

Periodic Table Definition

Let’s start with its basic definition;

• Periodic Table is the tabular arrangement of elements in the order of increasing atomic numbers, Hydrogen having the smallest atomic number, meanwhile, Oganesson having the highest atomic number of all.
• The vertical columns from top to bottom are called Groups in the periodic table, which are 18 in number.
• The horizontal rows from left to right are called Periods. There are 7 periods in the Periodic table.
• Here's the image showing the modern Periodic Table:

Arrangement of Modern Periodic Table

The periodic table has 118 elements till now, we can figure out a lot of things about an element just by looking at it, such as:

• Atomic weight is present at the top right corner.
• Atomic number is at the top left corner.
• Electronic configuration of valence shell can be seen at the bottom left corner.

Consider the following example for better understanding:

Groups and Periods

As I have mentioned earlier, elements are arranged in an order of increasing atomic number in the form of rows and columns called periods and groups respectively. When I was a student I was always confused about period and group, so here's a trick if you're struggling too, just cram it as " top to bottom in a group" so whenever you'll think of a group you'd have an idea what exactly you're thinking about.

Blocks in Periodic Table

• Periodic table can be divided into four blocks, s, p, d and f.
• Have you ever thought why they are named s, d and p? They could have been named a, b, c or d! Let me figure this out for you:
• Blocks are named after the electronic configuration of valence electrons.
• For example, all s block elements have their valence electrons in s subshell and same goes for p block elements, interesting! Isn't it?

Groups in Periodic Table

There are 18 groups in periodic table which are named as:

• Group 1 comprising of Alkali Metals
• Group 2 having Alkaline Earth metals
• Group 3 – Group 12 housing Transition elements
• Group 13 housing Boron family
• Group 14 with Carbon family
• Group 15 containing Nitrogen family
• Group 16 having Oxygen family
• Group 17 with Halogens
• Group 18 containing Inert or Noble gases

Group 1 of Periodic Table: Alkali Metals

• This is the very first group of the periodic table and its members are called Alkali metals with elements Hydrogen being the lightest having an atomic number of 1, succeeded by Helium, Sodium, Potassium, Rubidium, lastly Cesium and Francium in the family.
• You might have thought why they are called alkali metals? Upon reacting with water these metals give strong alkalis, naming them as alkali metals. 

Physical Properties of Alkali Metals:

• Physically they are shiny, lustrous and sleek in appearance.

Chemical Properties of Alkali Metals:

• Alkali metals are highly reactive and their reactivity increases down the group.
• All of them have low Ionization energies so it is easier for them to lose an electron.
• They are mostly found in an oxidation state of +1.

Group 2 of Periodic Table

• Group 2 elements were discovered by Humphry, it contains highly reactive elements which result in oxides upon reacting with oxygen, and these oxides when dissolved in water produce strong alkali solutions taking their name as Alkaline Earth Metals.
• Alkaline earth metals have Beryllium, Magnesium, Calcium, Strontium, Barium and Radium in the group with an order of increasing atomic number.
• They are very reactive and so are considered strong reducing agents. Do you know what a reducing agent is?

“A reducing agent is a chemical species which can lose electrons easily in a chemical reaction and hence oxidizes itself”. Chemical Properties of Alkaline Earth Metals:

• They are highly reactive in their natural forms being strong reducing agents.
• They can easily become a cation with 2+ charge by losing two electrons from their outermost shell.

Physical Properties of Alkaline Earth Metals:

• They are highly abundant in nature.
• They have a shiny appearance and are often silvery-white in color.
• They have a lot of commercial applications.

Group 3-12 of Periodic Table

• This group comprises of the d and f block elements which are found in the center of the periodic table and are famously known as Transition Elements.
• d block elements are called outer transition elements meanwhile f block elements are called inner transition elements despite the fact that they occupy totally opposite places in the periodic table.
• You might have thought why d and f block elements are called transition elements?

Here is a simple answer to the question, the d and f block elements have their properties in between s and p blocks elements, some of them show the characteristic behaviors of s block that is Group 1 and 2 elements by losing electrons meanwhile some of the elements resemble p block elements by gaining electrons during a chemical reaction in this way they take their name as transition elements. Following are the families found in the transitional groups:

• Group 3 has Scandium family.
• Group 4 houses elements like Titanium making them Titanium family.
• Group 5 is called Vanadium family.
• Group 6 has Chromium family having very famous members like Tungsten.
• Group 7 is Manganese family.
• Group 8 is the Iron family, who is not familiar with this super famous element? We all have been hearing it since childhood.
• Group 9 is the Cobalt family.
• Group 10 has Nickel family with its famous members like Platinum, you all have heard of Platinum rings and bands right?
• Group 11 has been crowned by Copper along with Silver-Ag as its succeeding member.
• Group 12 lastly forms the Zinc family with its ever useful and renowned member Mercury which is the only metal found in the liquid state on room temperature, that's is the reason it is commonly used in Thermometers! 

Lanthanides and Actinides:

• These are f block, inner transitional elements with unique properties as clearly visible by their names.

Actinides have the following properties:

• Atomic number ranges from 89 to 103
• Radioactive in nature
• Valence electrons in 5f orbitals
• Oxidation state can be up to +6

Lanthanides have the following properties:

• Atomic number ranges from 57 to 71
• Valence electrons are present in 4f orbitals
• They are not radioactive in nature
• Can maximally go up to +4 oxidation state

Chemical Properties:

• They are excellent conductors of electricity because of the formation of electronic pool in their structure, when I was in school I used to think of the best conductor of all the Transition Elements, at that time I didn't have Google so I could have searched, I have got to know now, it's Silver which is the best of all these metals in terms of conductivity.
• They form complex ions and colored compounds as a product of their chemical reactions.
• They have high melting and boiling points. 

Physical Properties:

• These groups have metals which are Malleable and Ductile, which in simple terms mean; they can be turned into sheets and wires.
• In terms of physical appearance they have shiny and lustrous appearance, if you forget in any case the properties possessed by these groups just recall that Silver is a transition metal with a shiny, lustrous appearance and can be turned into jewelry too. 

Group 13 of Periodic Table

• Group 13 elements are also called Boron family with other elements like Aluminum, Gallium, Indium, Thallium and Nihonium in the order of increasing atomic number, Boron being the smallest and Nihonium being the largest element but synthetic in nature.
• Group 13 elements are also called Triels or trivalent because of the presence of three electrons in their valence shells.

Chemical Properties and Usage:

• You must have been thinking about the chemical properties of this group! So let me tell you, they are highly abundant in nature and reactive too they can react with hydrogen, oxygen and halogens forming hydrides, oxides and halides respectively.
• Boron family has isotopes too which have wide applications in medical field.
• From Boron being used in ceramics to the Aluminum which is the most abundant metal of earth crust being used in construction and metal works, Indium and Gallium are not lesser than any of the other group members, they have a lot of commercial applications too.
• Thallium is used in the production of poisons for killing reptiles and rodents.

Group 14 of Periodic Table

• This is known as the famous Carbon family with its top most members as Carbon and Silicon.

Physical Properties and Usage:

• When thinking of Carbon one must recalls the chemical reactions in Organic Chemistry which were never an easy pill to swallow! Phewww! Carbon has the unique bonding ability to form long chains which is called “Catenation”, all thanks to catenation we have another branch of chemistry known as Organic chemistry. Not only organic chemistry, but Diamond and Graphite are also the gifts of Carbon being their allotropes.

• Next to Carbon is Silicon which is one the most abundant elements on the planet Earth and is commercially used in the formation of semiconductor diodes and chips used in various technological devices. Germanium is used in the formation of semiconductors as well.
• Who's not aware of lead and tin? Both of the elements are used commercially because of their stable nature in the formation of cans, nuts and bolts.

Chemical Properties of Carbon Family

• Carbon family has four electrons in its valence shells which results in covalent bonding.
• Covalent bonding is the reason of their high melting and boiling points.
• All of the group members form hydrides, oxides and halides reacting with hydrogen, oxygen and halogens respectively.
• They are usually found in the oxidation states of +3, -4 and +4.

Group 15 of Periodic Table

• Group 15 is also known as the Nitrogen family or Pnictogens.
• The name Pnictogens points to the ability of nitrogen to choke in the absence of Oxygen. Other members of the group include Phosphorus, Arsenic and Bismuth.

Reactivity:

• Nitrogen and Phosphorus act as non-metals whereas Arsenic and Antimony have proven themselves to be metalloids, meanwhile the last member Bismuth is a metal.
• They form covalent compounds due to the presence of five electrons in their valence shell and are mostly found in the oxidation state of +3 or +5

Usage:

• Nitrogen is found abundantly in nature, you might have thought of it earlier while studying Nitrogen Cycle in your school textbooks. Chefs using liquid nitrogen to freeze a dessert instantly has always fascinated me, it is due to its unique ability to stay non-reactive at room temperature. Nitrogen is used in fertilizers and has countless commercial applications.
• Meanwhile other members of the family are not less than any other element, Phosphorus is highly flammable and used in manufacturing explosives and fireworks and has three forms red, black and white.
• Arsenic being poisonous founds its use in fertilizers.
• Bismuth is used in pharmaceutical industry for production of several beneficial drugs.

Group 16 of Periodic Table

• Elements of group 16 are also called Chalcogens, as interesting as the name sounds, the reason behind the name lies in the ore forming ability of these elements.
• Oxygen, Sulphur, Selenium, Tellurium and Polonium are the members of this groups.

Chemical Reactivity:

• Chemical reactivity increase down the group with the increase in atomic number.
• Total number of valence electrons are six in the family which encourage covalent bonding, as it is very difficult to loose six electrons meanwhile gaining two electrons to complete the octet would be easier, isn't it?
• Oxidation state of -2 is most common among the group, Sulphur can exist as +4 and +6 as well.

Usage:

• Oxygen is the most abundant one, now a days we have seen an enormous demand for clinical oxygen in Covid stricken patients, different types of oxygen is obtained by fractional distillation in plants under specific conditions, many industries such as steel mills use oxygen in their processes as well.
• Sulphur is found in the form of ores and is used in the formation of fungicides and several medicines.
• Selenium and tellurium are photoconductive meanwhile polonium is a rare radioactive metal.

Group 17 of Periodic Table

• Elements of the group 17 are called Halogens and are highly reactive, students often ask about the reason behind their unique name, so cracking it for you Halogen is a Greek word which has been derived from two words “Halo” meaning “Salt” and “Gen” means “to produce something”, the term collectively means “salt producing”.
• These elements are called halogens because of their salt producing ability when they react with an alkali metal. Halogens include Fluorine, Chlorine, Bromine, and Iodine.

Chemical Reactivity:

• Fluorine is the most reactive element of this group.
• All the halogens have seven electrons in their outermost shell so they can easily gain an electron in a chemical reaction. They have a usual oxidation state of -1.
• They are good oxidizing agents because of their higher electron affinities.

Physical Properties:

• Halogens turn into a darker color as we move from top to bottom in the group. Fluorine being pale yellow, meanwhile Chlorine has a greenish yellow tint, Bromine is found in brown color and lastly Iodine has a purple hue.
• First two elements are gases, Bromine is a liquid and Iodine exists as a solid at room temperature.

Usage:

• You must have watched a million ads on the television about fluoride toothpaste, yeah! It helps in preventing tooth decay. Fluorine has always been a fundamental part of dental industry.
• Chlorine is a bleaching agent and used to purify water as well especially in swimming pools.
• Bromine is used for water purification, pesticide production and in pharmaceutical companies as well.
• Using Iodized salt is a common practice in many countries, because it helps in improving growth and metabolism when used in appropriate amounts. Iodine is also used as a topical antiseptic agent.

Group 18 of Periodic Table

Elements of group 18 are also known as Noble gases, who is termed as a noble? A person who never mess around with anyone, same is the state of Noble gases, they're inert and don't react with anything because of the very obvious reason, can you guess? Yeah! You guessed it right. They have a complete octet, they don't have to reach out anyone to be stable. Noble gases include Helium, Neon, Argon, Krypton and Xenon. Physical and Chemical Properties:

• Noble gases are colorless and odorless in normal conditions.
• They have low melting and boiling points.
• Noble gases can be used as oxidizing agents under special circumstances.

 Usage and Applications:

• We all have seen ice cream cone as a lighting sign with popping colors outside the ice cream parlor, they're called Neon signs, the gas in them is not exactly neon every time but is always a Noble gas. All Noble gases give out their specific color when lighted.
• Helium balloons have also remained eye candy to every one of us in our childhoods as Helium gas is very light in nature that is the reason it is used for filling balloons.
• One of the latest applications of the noble gases are Excimers, these are the diamer forms of Noble gases and have wide applications in medical field. They help in eye surgery and myocardial repair.

Trends in the Periodic Table

In order to understand the trends found in the periodic table we must understand the term periodicity “Periodicity refers to the cyclical trend in the chemical and physical properties of the elements with increasing atomic number.” Periodicity help us understand and predict various trends among the family members of same group just like offspring from same parents have some general characteristics in common , they all may have blue eyes or black hair or anything in common as a family, families of the periodic table also have common characteristics in the similar ways.  Some of the periodic trends in the periodic table are;

• Atomic radii.
• Ionization energy.
• Electron affinity.
• Electronegativity.
• Shielding effect.
• Metallic and Nonmetallic  behavior.

Atomic Radii Trend in Periodic Table

• Atomic radii is one of the core aspects that can make the elements behave in a certain way in a chemical reaction.

Factors effecting the Atomic Radii:

• Atomic number
• Number of shells : As we move from top to bottom in a Group the atomic number increases, this gradual increase in the atomic number makes the atomic radii larger and larger by adding in a number of shells

Trend across the Group:

• When the atomic radii grows larger from top to bottom in a group, the hold of the nucleus on the valence electrons decreases.
• This decreased force on the valence electrons increases the reactivity of an element.
• So we can conclude that as we move towards the bottom an increase in reactivity of the elements can be predicted, why? Because they are less bounded by the nuclear forces and are free to react.

Trend across the Period:

• Similarly when moving left to right in a period , atomic radii decreases due to the decrease in atomic number and hence reactivity of the elements decreases , all thanks to strong grip of the nuclear forces on the valence electrons which pulls the electronic cloud towards itself.

Largest and smallest element With respect to Radius

• You might have thought which is the largest and the smallest element in terms of radius? Let me tell you, the smallest one is Helium meanwhile the largest one is Francium.

Exceptional Behavior:

• There are a few exceptions in the normal trend as well because all the five fingers can never be same.
• Ooxygen has a larger radius than its neighboring nitrogen all because nitrogen has seven proton in its nucleus meanwhile oxygen has eight so it has larger ionization energy value.

Ionization energy Trend in Periodic Table

Ionization energy can be defined as:

• "Ionization energy is the amount of energy required to remove the loosely bound electron from the outermost shell of a neutral gaseous atom in its ground state".

Factors effecting ionization energy:

• Atomic radius
• Shielding effect
• Increased atomic number

Trend across the Group:

• Ionization energy is mainly governed by the atomic radii, as we move from top to bottom in a group atomic radii increases, which results in a decline in effective nuclear charge.
• A declined effective nuclear charge and an increased shielding effect leads to the lesser binding force on the valence electrons, when the valence electrons have less nuclear force on them, what would happen? That would be easy to remove by giving a small amount of energy, this energy is called the ionization energy.
• Summing up we can say ionization energy decreases down the group as we move towards the bottom.

Trend across the Period:

• When moving across a period from left to right, the effective nuclear charge increases leading to a decrease in atomic radii, ultimately shielding effect also decreases, all these factors make it highly difficult to remove an electron rather they would prefer to gain an electron or two for stability.
• So we can say that ionization energy increases from left to right in a period. 

Types of ionization energy; There are two types of ionization energy

• First ionization energy
• Second ionization energy

Following is an example of first and second ionization energy:

• First ionization energy is the energy required to remove the electrons from a neutral gaseous atom.
• Second ionization energy refers to the amount of energy required for removal of an electron from the molecular ion or cation.

So here is an understandable clear fact which must not be missed in any way; second ionization energy is always higher than the first one. Let me explain why! It happens because of the increase of additional positive charge on the electronic cloud because of the removal of electron, nucleus tightens its grip on the valence shell, and hence a large amount of energy is required to remove an electron which is always higher than the first one.

Shielding effect Trend in Periodic Table

Before studying the shielding effect let's discuss what does a shield do? A shield masks or hinders the effect of any force applied to a body, when same principle is applied to an atom, we can define shielding effect as:

• "When the inner shell electrons shield the effect of nucleus, decreasing the effective nuclear charge on the valence electrons, then this phenomenon is called shielding effect".

Shielding effect decreases the effective nuclear charge experienced by the valence electrons. So now you must be thinking what is effective nuclear charge?

• "Effective nuclear charge is the average net positive charge experienced by an electron from its nucleus".

Trend across the Group:

• As the atomic number increases the number of shells in each atom also increase, with every additional shell there's a greater shielding effect on the valence electrons.

Trend across the Period:

• Shielding effect increases from top to bottom in a group meanwhile it remains constant from left to right in a period.
• The sole reason behind constant shielding effect from left to right is the same number of shells in all the elements residing in a period, no additional shell leads to constant shielding effect. Simple!

Electronegativity Trend in Periodic Table

Electronegativity can be defined as,

• "The ability of an atom to attract the shared pair of electrons partially or completely towards itself when bonded to another atom in a molecule".

Whenever we study covalent bonds we often talk about the poles, this is a polar covalent bond that is a non-polar one, you might have thought which causes this polarity within the molecules? So now you have your answer, electronegativity difference causes polarity in a molecule. Electronegativity values of certain elements have already been determined, the difference between their values i.e. the electronegativity difference help us predict the nature of bond, whether it would be ionic, covalent, slightly polar or moderately polar in nature. Factors effecting Electronegativity: Electronegativity of an element is effected by the following:

• Atomic number
• Number of valence electrons
• Shielding effect and effective nuclear charge
• Atomic radii

Trend across the period:

• In the periodic table electronegativity increases across the period when moving left to right, fluorine being crowned as the most electronegative element of all having the value if 4.
• All thanks to the strong grip of nucleus on the electronic cloud, which never lets anyone escape its grip!

Trend across the group:

• Meanwhile due to increase in atomic number and shielding effect, electronegativity decreases down the group, so these elements have lesser tendency to keep the shared pair of the electrons towards themselves so we can say that the left bottom elements of the periodic table can never be good keepers of the shared electrons.

Electron Affinity Trend in Periodic Table

Electron affinity is the opposite of Ionization energy which we have discussed earlier, ionization energy is the energy required for removal of an electron on the other hand electron affinity is the energy required for the addition of an electron to an atom.

• Electron affinity can be defined as “the amount of energy released when an electron is added to a neutral gaseous atom turning it into an anion.”

As energy is being released the process is exothermic in nature.

• Halogens have highest electron affinities in the periodic table
• Metals have lowest electron affinities in the periodic table.

Factors effecting electron affinity: Electron affinity is effected by the following:

• Atomic number
• Number of valence electrons
• Shielding effect and effective nuclear charge
• Atomic radii.

Trend across the Group:

• When we move from top to bottom in a group, atomic radii increases resulting in a weak nuclear charge on the valence electrons.
• So what you think now what would be the trend? I hope you can easily guess it by now! Yes you are right, electron affinity would decrease from top to bottom in a group.

Trend across the Period:

• From left to right in a period, effective nuclear charge never let anyone move astray like street animals, so it has strong hold on the valence shell, adding an electron releases a huge amount of energy which corresponds to higher electron affinity values increasing the electron affinity values gradually across the period.

Element with highest electron affinity:

• Chlorine has the highest electron affinity of all the elements even higher than fluorine because of its structural compactness as compared to fluorine.

Metallic Character Trend in Periodic Table

• Metallic character is one of the most interesting properties possessed by elements, as indicated by name, “metallic character is the ability of metal to lose electron during a chemical reaction.”
• Metallic character is observed due to the least ionization energy values of the metals which tend to loose electrons easily to remain stable rather than keeping them.

Electron pool theory: While discussing metallic character we must not forget electronic pool theory , Electronic pool theory is about the metallic character of the metals which tend to lose all their valence electrons turning it into a pool of electrons around a positive charge , this is the reason of their electrical conductivity, now you know! Trend across the Group: Metallic character increases down the group because of the following factors that come into play;

• Increased atomic number.
• Increased atomic radii.
• Lesser ionization energy.

In the presence of above factors, metals tend to lose electrons easily. Trend across the Period:

• From left to right in the periods metallic character decreases due to higher effective nuclear charge and smaller electronic clouds, so it is extremely difficult to lose an electron and exhibit metallic character.

Most and Least Metallic Elements:

• The most metallic of all the elements is Francium, meanwhile Fluorine is the least metallic or non-metallic element of the periodic table.

So that was all about periodic table and its groups with their brief introduction and general trends, I hope it helped you clear some general misconceptions we all have in our minds regarding the topic. See you with another topic soon, have a good day!

What is Chemistry? Definition, Branches, Books and Scientists

Hello Friends! I hope you all are doing well. Today, I am going to share with you a very basic and detailed tutorial on What is Chemistry? We will also discuss Chemistry types, popular Chemistry books, famous Chemists and their great inventions in the field of Chemistry etc.  When you hear the word Chemistry, you may think, it is only concerned to the study of chemicals, dangerous substances etc. But let me surprise you, Chemistry is also known as the Central Science means it is the insight study of almost everything around us. I just remembered very comprehensive Chemistry definition by American Chemical Society, “Everything you touch, see, smell and hear involves Chemistry and chemicals”. Scientist divided Physical sciences in 5 major disciplines in the 19th century.

• Chemistry.
• Physics
• Astronomy.
• Meteorology.
• Geology.

What is Chemistry?

Chemistry is one of the most vital & fundamental branches of science, concerned with the deep study of matter, its properties, composition (chemical) and use. And you must know that everything around us is matter. It means Chemistry involves in our everyday life task, from cooking to cleaning. Chemistry is actually the mixture of physics and biology. Because of its fundamentally understanding with the basic and applied scientific disciplines. Now, let’s have a look at the proper definition of Chemistry.

Chemistry Definition

• Chemistry deals with the study of elements (i.e. atoms, molecules, compounds, ions etc.) and their chemical composition, characteristics, structure, and chemical reactions.
• Chemistry also studies the chemical interaction (bonding) between elements, atoms and molecules. It studies the reasons of bonding and their effects.
• Further, chemistry is also concerned with the energies released or abosrbed by different molecules.

Why is Chemistry important?

• Chemical reactions are taking places every second around us. From the digestion food to making of food from plants, everything is happening due to chemical reactions. Our whole body is made up of chemical compounds. And it is Chemistry, concerned to study these reactions for our betterment. Let’s discuss the most common examples:
• The creams and sunscreens, we used in our daily life to protect our skin form UV radiation from sun, are made of organic and inorganic compounds, and directly related to Chemistry.
• The process of photosynthesis is a chemical reaction; plants use water, carbon dioxide and sunlight to prepare food.
• The detergents we are using for hygienic purpose are also examples of emulsion, which is also chemical reaction. The soaps are made from the chemical process call saponification.

Chemistry Branches

On the base of the studying matters, changes and types of the systems, Chemistry is sub-divided into the following categories. Let’s discuss branches of Chemistry briefly for better understanding.

1. Organic Chemistry

Organic Chemistry is the field of study, mainly focuses on the characteristics study about carbon atom. Including the experimental study on the structure and composition of other atoms such as oxygen (O), nitrogen (N), hydrogen (H) etc.

2. Inorganic Chemistry

Inorganic Chemistry is the branch of Chemistry, not focused on the study of carbon. But you know carbon is essential atom in many inorganic compounds. Therefore, there has been investigated another field of study is organometallic Chemistry, a mixture study between organic and inorganic Chemistry.

3. Analytical Chemistry

This branch of Chemistry is the insight study of elements in mixture form. Its main focus is to identify and analyze these materials. It invents the materials & methods to analyze these material. As well as discovered the separation techniques.

4. Physical Chemistry

The physical Chemistry is the branch of Chemistry to deeply examine the behavior of atoms, elements, chemicals, compounds and molecules, and proposed the fundamental laws of Chemistry.

5. Environmental Chemistry

It is basically the study of environmental chemical and their composition.

6. Bio-chemistry

This branch of Chemistry mainly focuses on discovering the inner information during the examination of biological systems using chemical laws. It also provides the revelation of the link between the functional properties and structure of biological systems.

7. Nuclear Chemistry

It is the type of Chemistry, concentrated in the experimental study about the radioactive elements, their reactions and properties. Simply, this field is all related with the study of radioactivity.

8. Biophysical Chemistry

It is the sub-discipline of Chemistry, basically deals with the biological macromolecules and their properties.

9. Polymer Chemistry

It is the field of Chemistry, fundamentally related on the study of formation of chemical, properties, and structure of macromolecules & polymers.

Chemistry top concerns

Chemistry also provides insight to the chemical bonds and formation of their interaction with each other. It studies the chemical bonding through which atoms are linked. There are 2 types of chemical bonds:

• Covalent bonds (also named as primary chemical bond).
• Metallic bonds.
• Ionic bonds.

Above are the primary bonds, whereas the secondary chemical bonds are:

• Hydrogen bonds.
• Van der Waals force.

Relationship of Chemistry with Other Areas of Science

Due to the immense areas of concerns in the universe, science sub-divided into the following areas, mainly focus on the universal aspects. The primary three categories under science are discussed below:

1. The Formal Sciences

Also named as “language of science”. Because of its main focus on the studying of languages. For example, the logic and math are the example of this area of science.

2. The Natural Sciences

This category involves the experimental study about occurring of natural phenomena in the universe. Physics, Biology and Chemistry are lying under this discipline.

3. The Social Sciences

The social sciences studying the human nature and behavior as well as their relation with the societies. The main disciplines falls under this category are: Psychology, economy and sociology. Have a look on below picture; it will help you to understand the relationship of branch chemistry with other disciples of science.

Chemistry books

Chemistry is one of my favorite subjects. Now I am going to share some famous and best reading text-books of Chemistry. You can download or buy these books, I am sure it will be worth reading Chemistry books.

1. An Introduction to General, Organic, and Biological

It is a precise and easy Chemistry book to understand written by Karen C. Timberlake. As form the name of book, you have got an idea about the content of this book. This book of Chemistry is all about the organic area of Chemistry as well the biological Chemistry. This book has revealed the relation of Chemistry with health and environment.

2. A Molecular Approach (4th Edition)

This is the book of Chemistry, many institutes loved to recommend to their students. The written by if this book is Nivaldo J. Tro.  It is generally a well written book, and got very fame. The written by explained about the data interpretation and analyses. It gives the digital and analytical experience to students.

3. Chemistry For Dummies

Let’s talk about another impressive Chemistry book written by John T. Moore. This book explains all the chemical reaction happening in the formation of soap, oil and soda. This book provides insight study of chemical methods, techniques, basic principles and fundamental concepts of Chemistry. The language used also very simple and easy to understand for students.

Few other Chemistry books

Some other famous Chemistry Books are:

Popular Books of Chemistry
No.	Book Name	Author
1	Napoleon's Buttons: How 17 Molecules Changed History	Penny Le Couteur
2	The Elements: A Visual Exploration of Every Known Atom in the Universe	Theodore Gray
3	The Poisoner's Handbook: Murder and the Birth of Forensic Medicine in Jazz Age New York	Deborah Blum
4	Uncle Tungsten	Oliver Sacks
5	General Chemistry	Linus Pauling
6	A Chemical History of a Candle	Michael Faraday
7	A Short History of Nearly Everything	Bill Bryson
8	The 13th Element: The Sordid Tale of Murder, Fire, and Phosphorus	John Emsley
9	Blue Dreams: The Science and the Story of the Drugs that Changed Our Minds	Lauren Slater
10	The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements	Sam Kean
11	Molecules: The Elements and the Architecture of Everything	Theodore Gray
12	Chemistry of Space	David E. Newton
13	Periodic Tales: The Curious Lives of the Elements	Hugh Aldersey-Williams
14	Ingredients: A Visual Exploration of 75 Additives & 25 Food Products	Steve Ettlinger
15	The Alchemy of Air: A Jewish Genius, a Doomed Tycoon, and the Scientific Discovery That Fed the World but Fueled the Rise of Hitler	Thomas Hager
16	Theo Gray's Mad Science: Experiments You Can Do at Home - But Probably Shouldn't	Theodore Gray
17	The Double Helix	James D. Watson
18	Oxygen: The Molecule That Made the World	Nick Lane
19	Connecting the Drops: A Citizens' Guide to Protecting Water Resources	Karen Schneller-McDonald
20	Uranium: War, Energy and the Rock That Shaped the World	Tom Zoellner
21	Choked: Life and Breath in the Age of Air Pollution	Beth Gardiner
22	What Einstein Told His Cook: Kitchen Science Explained	Robert L. Wolke
23	Bottled Lightning: Superbatteries, Electric Cars, and the New Lithium Economy	Seth Fletcher
24	Strange Chemistry: The Stories Your Chemistry Teacher Wouldn't Tell You	Steven Farmer
25	The Electric Life of Michael Faraday	Alan W. Hirshfeld

Popular Chemists of All Times

There is a long list of famous scientist whom contributed the field of Chemistry. Let’s have a look of top chemists and their achievements below:

Famous Chemists
No.	Chemists Name	Achievement
1.	Amedeo Avogadro	First time give the idea about elements can exist in molecular form, as well as individual form. Also give Avogadro’s law.
2.	Jacob Berzelius	He is the founder of measurement of atomic weights of chemicals. He also revealed new elements i.e. thorium, cerium &. selenium
3.	Niels Bohr	He discovered the theory of quantum mechanics when he observed electrons orbiting around the shell.
4.	Robert Boyle	He founded the two sub-fields of chemistry, named as alchemy and mysticism. He also discovered many elements, defined them. He invented the Boyle’s law also known as first gas law.
5.	Lawrence Bragg	He invented the position of different atoms using x-ray diffraction in solids.
6.	Hennig Brand	He founded the elements, phosphorus. And was the first scientist in chemistry history, discovered the chemical element.
7.	Georg Brandt	He is the first Chemists who discovered the new metal ‘cobalt’. He proposed the theories for people of making gold.
8.	Robert Bunsen	He invented the following elements (cesium & rubidium). He also discovered the zinc & carbon batteries, he was the inventor of flash positioning. He also proposed hoe the geysers works.
10.	Marie Curie	He invented the radium and polonium elements. He gives s important information about radioactivity and radioactive elements. He first time performed the tumour treatment using radiations.
11.	John Dalton	He gives the Dalton’s theory, considered as the base of Chemistry. Moreover, discovered Gay-Lussac’s law with respect to volume, temp & pressure of gas.
12.	Democritus	He proposed the atomic theory about the motion interaction of tiny particles. He did search and study on the starts and their milky appearance.
13.	Empedocles	He gives the natural sciences theories, invented four elements.
14.	Michael Faraday	He invented the electromagnetic induction. More he discovered the Faradays law, link between the magnetism & light. He also explains the first room temp of a gas. And discovered benzene.
15.	Rosalind Franklin	He gives the experimental data about the DNA structure. He also discovered the two forms of DNA.
16.	Willard Gibbs	He invented the vector concept and modern science. He also focused on chemical thermodynamics.
17.	George de Hevesy	He discovered 72 elements. He also invented pioneered isotopes to find the chemicals process as well as biological one. He discovered about animals and plant utilization of chemical elements as nutrients.
18.	Fred Hoyle	He invented the naturally founded elements. And set them on the periodic table.

Few remarkable Chemists

Here's the list of few other remarkable Chemists:

• Natalie Ahn, American.
• English Chemist, A. Aikin.
• H. C. Allen, American.
• German Chemist, R. Abegg.
• German Chemist, F. Accum.
• American expert, J. Alexander.
• Swedish Chemist, S. Arrhenius.
• American Chemist, P. Agre.
• American Chemist, A. Almutairi.
• American Chemist, H. Burton Adkins.
• Kuwaiti Chemist, F. Al-Kharafi.
• American Chemist, L. A. Cohen.
• American Chemist, E. Lucille Allen.
• S. Altman won Nobel Prize in Chemistry.
• V.Ashby, American.
• Fr. W.Aston won Nobel Prize in Chemistry.
• G. L. Anderson, American.
• Australian Chemist, A. Albert.
• B. Christian won Nobel Prize in Chemistry.
• American Chemist, A. J. Arduengo.
• American Chemist, B. Askins.
• German chemists, G. Agricola.
• Dutch Chemist, A. Eduard van Arkel.
• Physical English Chemist, J. Albery.
• Brazilian Chemist, O. A. Ceva Antunes.
• American N. Chemist, L. B. Asprey.
• Italian Chemist, A. Angeli.
• Johan August A., Swedish Chemist.
• German Chemist, K. Alder.
• Swedish Chemist, Ka.Aurivillius.
• English Chemist, F. Abel.

I hope this article will be helpful for you all to understand the basics of chemistry, its branches, importance, and famous books & chemists of all times. Try to read the refer books above for more knowledge, those are really worth reading.