NCERT Solutions for Class 11 Chemistry Chapter 4 Chemical Bonding and Molecular Structure

Short Note:

• Ionic (Electrovalent) Bond: formed by the complete transfer of electrons from one atom to another, resulting in oppositely charged ions held together by electrostatic attraction.

• Covalent Bond: formed by the mutual sharing of electron pairs between two atoms, as described by the Lewis dot structure and the octet rule.

Short Note:

• Valence Shell Electron Pair Repulsion (VSEPR) Theory predicts molecular shape based on the principle that electron pairs (bonding and lone) around a central atom arrange themselves to minimise repulsion.

• Lone pair – lone pair repulsion > lone pair – bond pair repulsion > bond pair – bond pair repulsion.

Short Note:

• Hybridisation is the intermixing of atomic orbitals of slightly different energies to form new equivalent orbitals (hybrid orbitals) of same energy and shape.

• Common types: sp (linear, 180°), sp² (trigonal planar, 120°), sp³ (tetrahedral, 109.5°).

Short Note:

• Atomic orbitals combine to form bonding molecular orbitals (lower energy, stabilising) and antibonding molecular orbitals (higher energy, destabilising).

• Bond Order = ½ (number of electrons in bonding MOs − number of electrons in antibonding MOs). A higher bond order generally means a more stable, shorter bond.