Chapter 4 — Chemical Bonding and Molecular Structure

Chemical Bonding and Molecular Structure explains how atoms combine to form stable molecules through ionic and covalent bonds, with geometries determined by electron pair repulsion, orbital overlap, and hybrid orbital formation.

Chapter 4 covers the Kössel-Lewis approach to bonding, the octet rule, ionic and covalent bond formation, lattice enthalpy, bond parameters (length, angle, enthalpy, order), resonance structures, VSEPR theory for predicting molecular shapes, valence bond theory with orbital overlap concepts, sp/sp2/sp3 and sp3d/sp3d2 hybridization, molecular orbital theory with bonding and antibonding orbitals, bonding in homonuclear diatomic molecules (H2, O2, N2), and hydrogen bonding (intermolecular and intramolecular types).

1. 01Kössel and Lewis explained chemical bonding through electron transfer (ionic) or sharing (covalent) to achieve noble gas configurations (octet rule).
2. 02Bond parameters—length, angle, enthalpy, and order—determine molecular properties and can be measured by spectroscopy and X-ray diffraction.
3. 03VSEPR theory predicts molecular geometry by minimizing electron pair repulsion: lone pair > bond pair repulsions determine shape.
4. 04Valence bond theory uses atomic orbital overlap (σ and π bonds) and hybridization (sp, sp², sp³, sp³d, sp³d²) to explain bond formation and molecular geometry.
5. 05Molecular orbital theory describes bonding via linear combination of atomic orbitals (LCAO), forming bonding (lower energy) and antibonding (higher energy) orbitals.
6. 06Hydrogen bonding forms between highly electronegative atoms (F, O, N) and hydrogen, existing as intermolecular (between molecules) or intramolecular (within a molecule) types.