Molecular orbital concept of bonding (elementary pictorial approach):sigma and pi-bonds, multiple bonding, MO diagrams of H2, F2, O2, C2, B2, CO, NO, CN-, HF, and H2O; bond orders, bond lengths, Walsh Diagram. Coordinate bonding: Lewis acid-base adducts (examples), double salts and complex salts.
Hydrogen bonding: effect on the physical properties of compounds of the main group elements.
Metallic bonding: qualitative idea of band theory, conducting, semi conducting and insulating properties with examples from main group elements.