Inorganic Chemistry (B.A./B.Sc) 1st Sem Previous Year Solved Question Paper 2022

The Valence Shell Electron Pair Repulsion (VSEPR) theory is a model used to predict the shapes of molecules based on the repulsion between electron pairs in the valence shell of atoms. Here are the key postulates of the VSEPR theory:

1. **Electron Pair Repulsion**: The shape of a molecule is determined by the repulsion between electron pairs in the valence shell of the central atom. Electron pairs, whether bonding or nonbonding (lone pairs), repel each other.

2. **Minimization of Electron Pair Repulsion**: Molecules adopt shapes that minimize the repulsion between electron pairs. The arrangement that minimizes electrostatic repulsion is the most stable.

3. **Lone Pairs and Bonded Pairs**: Lone pairs of electrons exert greater repulsion than bonded pairs. As a result, the presence of lone pairs influences the molecular geometry.

4. **Geometries Based on Electron Pair Arrangement**: The geometry of a molecule is determined by the arrangement of electron pairs around the central atom. It is defined by the positions of both bonding pairs and lone pairs.

Now, let’s draw the geometries of ClF and ICl based on the VSEPR theory:

In both ClF and ICl, the presence of a lone pair on the central atom results in bent or angular geometries with bond angles less than 120 degrees, as the lone pairs repel the bonding pairs, causing a distortion from the ideal tetrahedral angle.