Chemical Bonding

Chapter Overview

Chapter 3: Chemical Bonding covers the fundamental theories explaining how atoms combine to form molecules. It begins with electronegativity, factors affecting it, periodic trends, and how it determines bond nature (ionic vs. covalent) and covalent character. It also covers dipole moments, polar and nonpolar covalent bonds, and bond enthalpies.

The core of the chapter focuses on structural bonding models. This includes Valence Shell Electron Pair Repulsion (VSEPR) theory, describing shapes of molecules containing two to six electron pairs, expanded octets (hypervalency), and the pharmaceutical importance of VSEPR. It also explains Valence Bond Theory (VBT) with applications to H2, F2, HF, O2, N2 molecules, along with various hybridization types and coordinate covalent bonds.

Lastly, the chapter examines forces between molecules, detailing intermolecular forces (permanent dipole, London dispersion, and hydrogen bonding) alongside a comparison of relative bond strengths. It introduces Molecular Orbital Theory (MOT), explaining bonding/antibonding molecular orbitals, bond order calculations, relative energy levels, and MOT diagrams for homonuclear diatomic molecules like H2, He2, N2, O2, F2.