Hello Shanu,

The important topics in Chemical bonding are:

For JEE Main:

• Kossel - Lewis approach to chemical bond formation, concept of ionic and covalent bonds.
• Ionic Bonding: Formation of ionic bonds, factors affecting the formation of ionic bonds; calculation of lattice enthalpy.
• Covalent Bonding: Concept of electronegativity, Fajan's rule, dipole moment; Valence Shell Electron Pair Repulsion (VSEPR) theory and shapes of simple molecules.
• Quantum mechanical approach to covalent bonding:
• Valence bond theory - Its important features, concept of hybridization involving s, p and d orbitals; Resonance.
• Molecular Orbital Theory - Its important features, LCAOs, types of molecular orbitals (bonding, antibonding), sigma and pi-bonds, molecular orbital electronic configurations of homonuclear diatomic molecules, concept of bond order, bond length and bond energy.
• Elementary idea of metallic bonding. Hydrogen bonding and its applications.

For JEE Advanced (Chemical Bonding and Atomic Structure):

• Bohr model, spectrum of hydrogen atom, quantum numbers;
• Wave-particle duality,de Broglie hypothesis;
• Uncertainty principle;
• Qualitative quantum mechanical picture of hydrogen atom, shapes of s, p and d orbitals;
• Electronic configurations of elements (up to atomic number 36);
• Aufbau principle;
• Pauli’s exclusion principle and Hund’s rule;
• Orbital overlap and covalent bond;
• Hybridisation involving s, p and d orbitals only;
• Orbital energy diagrams for homonuclear diatomic species;
• Hydrogen bond; Polarity in molecules, dipole moment (qualitative aspects only);
• VSEPR model and shapes of molecules (linear, angular, triangular, square planar, pyramidal, square pyramidal, trigonal bipyramidal, tetrahedral and octahedral).

All the best!!