Chemical Bonding

Introduction

Chemical Bonding means the formation of a chemical bond between two or more atoms, molecules, or ions to give rise to a chemical compound. These chemical bonds are the force that keep the atoms together in the resulting compound.

Chemical bond

A chemical bond is an attraction between atoms, ions and molecules that allows the formation of chemical compounds. Therefore, it can be understood that chemical compounds are dependent on the toughness of the chemical bonds between its constituents; The more efficient the bonding between the constituents, the more stable the resulting compound would be.

The reverse also holds true; if the chemical bonding between the constituents is not strong, the consequence compound would lack steadiness and would easily undergo another reaction to give a steadier chemical compound (containing stronger bonds). To find stability and nobleness, the atoms aim to lose their energy.

At any moment, matter corresponds to another form of matter, a force is influenced on one by some other. When the forces are attractive in nature, the energy falls. When the forces are repulsive in nature, the energy rises. The attractive force that tie two atoms together is known as the chemical bond.

Important Theories on Chemical Bonding

Gilbert Lewis and Albrecht Kössel were the first scientists to explain the formation of chemical bonds successfully in the year of 1916. They described chemical bonding on the foundation of the inertness of noble gases.

Lewis Theory of Chemical Bonding

• An atom can be viewed as a positively charged ‘Kernel’ (the nucleus plus the inner electrons) and the outer shell.
• The outer shell can accommodate a maximum of eight electrons only.
• The eight electrons present in the outer shell occupy the corners of a cube which surround the ‘Kernel’.
• The atoms having octet configuration, that is, 8 electrons in the valence shell, thus exhibit a stable configuration.
• Atoms can achieve this stable configuration by forming chemical bonds with other atoms. This chemical bond can be created either by taking or giving an electron(s) (NaCl, MgCl2) or in some situation due to the sharing of an electron(e-) (F2).
• Only the electrons present in the outer shell, also known as the valence electrons take part in the formation of chemical bonds. Gilbert Lewis used specific symbolisation better known as Lewis symbols to demonstrate these last shell electrons.
• Generally, the valency of an element is either equal to the number of dots in the corresponding Lewis symbol or 8 minus the number of dots (or valence electrons).

Here, the number of dots that are around the particular symbol shows the number of valence electrons in that atom.

Kossel’s theory of Chemical Bonding

• Noble gases separate the highly electronegative halogens and the highly electropositive alkali metals.
• Halogens can form negatively charged ions by taking an electron. Whereas alkali metals can form positively charged ions by giving an electron.
• These negatively charged ions and positively charged ions have a noble gas configuration that is 8 electrons in the outermost shell. The common electronic configuration of noble gases (except helium) is given by ns2np6.
• As unlike charges attract each other these unlike charged particles are held together by a strong force of electrostatic attraction existing between them. For example, MgCl2, magnesium ions, and chlorine ions are bonded together by force of electrostatic attraction. This kind of chemical bonding that exist between two unlike charged particles is called electrovalent bond.

Explanation of Kossel Lewis Approach

In 1916 Lewis and Kossel succeeded in giving a successful demonstration based upon the notion of an electronic configuration of noble gases about why atoms combine to form molecules. Atoms of noble gases have small or no chances to combine among themselves or with atoms of other elements. This means that these atoms must be having stable electronic configurations and are not that reactive.

Due to the stable configuration, the noble gas atoms neither have any chances to gain or lose electrons and, therefore, their valency is zero. They are so unreactive that they even do not form diatomic molecules and exist as monatomic gaseous atoms.

Types of Chemical Bonds

When substances participate in chemical bonding and form compounds, the stability of the product can be decided by the type of chemical bonds it contains.

The type of chemical bonds that are formed vary in strength and properties. There are four types of chemical bonds which are formed by atoms or molecules to form compounds. These are:

• Ionic Bonds
• Covalent Bonds
• Hydrogen Bonds
• Polar Bonds

These types of bonds in compounds are formed by the loss, gain or sharing of electrons between two atoms/molecules.

Ionic Bonding

Ionic bonding is a chemical bonding which involves giving or taking of electrons from one atom or molecule to another. when an atom loses an electron and in turn gained by another atom. When such an electron exchange takes place, one atom develops a negative charge and is now called the anion.

Another atom develops a positive charge and is called the cation. The ionic bond becomes stronger from the difference in charge between the two given atoms, i.e The greater the charge disparity between the cation and the anion, the more strong will be the ionic bond.

Covalent Bond: A covalent bond is a bond that is formed by the sharing of electrons pairs between atoms. These electrons are known as shared electron pairs and bonding pairs.

Hydrogen Bonds: A hydrogen bond is a type of bond in which there is an electrostatic force of attraction between the atoms.

Polar Bonds: In General a polar bond is a type of covalent bond. A bond is said to be polar if  two or more atoms have significantly different electronegativities.They do not share electrons. 

Conclusion

All chemical bonding  takes place due to electrostatic attraction. When atoms combine through chemical bonding, they results in compounds—unique structures composed of two or more atoms. … In covalent compounds, atoms form covalent bonds that consist of electron pairs shared between two adjacent atomic nuclei.

Chemical bonding helps to join atoms or molecules together. It also helps molecules of the same or different substance to get together through joining to each other . Solid , liquid, or gaseous matter can occur in the nature due to chemical bonding