CBSE Class 12-science Answered

Dear Student,

The force of attraction that holds various constituents together in different chemical species is called a

chemical bond.

To understand the nature of chemical bonds, different theories have been put forward. These are

Kössel–Lewis approach, Valence Shell Electron Pair Repulsion (VSEPR) theory, Valence Bond (VB)

theory and Molecular Orbital (MO) theory.

Valence bond theory was put forward by Heitler and London. According to this theory, during the

formation of bonds between atoms, only the valence electrons from each bonded atom lose their

identity. The other electrons remain unaffected, and the formation of the bond is accompanied by the

release of energy.