Chemical Bonding and Molecular Structure – Notes

Kossel – Lewis Approach to Chemical Bond
In the nature, the system with more energy is less stable. In other words, the lowest energy state corresponds to the most stable state of the system.
So every system tends to attain stability by losing energy.
Atoms attain stability by the means of bond formation. The process of bond formation is associated with the lowering of energy of the system.
Kossel and Lewis developed electronic theory of valence or theory of chemical bonding to explain the chemical bond formation between the two atoms.
According to the electronic theory of valence, every atom tries to attain octet in its valence shell by losing or gaining or by sharing of electrons. This is known as the “Octet Rule”.
The electrostatic forces of attraction that holds the two oppositely charged ions together is known as “electrovalent bond”.

Ionic Bond
The formation of ionic bond depends upon the following three key factors: first, the ease of formation of a cation, second the ease of formation of an anion, and finally, the arrangement of the positive and negative ions in the ionic solid.