CHEMICAL BONDING
& MOLECULAR STRUCTURE
CLASS 11 CHEMISTRY • NCERT-ALIGNED KILLER NOTES
■ MASTER THIS CHAPTER ■ EXAM FOCUS
Lewis structures • VSEPR • Hybridisation • MOT • Shapes • Bond order • Formal charge • σ/π bonds
H-bonding
Big idea: Electron arrangement decides bonding, shape, polarity and many physical properties.
1. THE CORE CONCEPT
Octet rule: Atoms generally tend toward a noble-gas-like valence-shell configuration. Hydrogen follows the duplet rule.
Exceptions: incomplete octet (BeCl■, BF■), odd-electron species (NO, NO■), and expanded octet (PF■, SF■).
2. LEWIS STRUCTURES — 4 STEPS
Step What to do
1 Count total valence electrons; adjust for charge.
2 Choose the skeleton; H is never the central atom.
3 Make single bonds and complete terminal octets.
4 Put remaining electrons on the centre; make multiple bonds if needed.
Formal charge: FC = valence electrons − [non-bonding electrons + ½(bonding electrons)]. Prefer structures with small
formal charges.
Class 11 Chemistry • Chemical Bonding Page 1
& MOLECULAR STRUCTURE
CLASS 11 CHEMISTRY • NCERT-ALIGNED KILLER NOTES
■ MASTER THIS CHAPTER ■ EXAM FOCUS
Lewis structures • VSEPR • Hybridisation • MOT • Shapes • Bond order • Formal charge • σ/π bonds
H-bonding
Big idea: Electron arrangement decides bonding, shape, polarity and many physical properties.
1. THE CORE CONCEPT
Octet rule: Atoms generally tend toward a noble-gas-like valence-shell configuration. Hydrogen follows the duplet rule.
Exceptions: incomplete octet (BeCl■, BF■), odd-electron species (NO, NO■), and expanded octet (PF■, SF■).
2. LEWIS STRUCTURES — 4 STEPS
Step What to do
1 Count total valence electrons; adjust for charge.
2 Choose the skeleton; H is never the central atom.
3 Make single bonds and complete terminal octets.
4 Put remaining electrons on the centre; make multiple bonds if needed.
Formal charge: FC = valence electrons − [non-bonding electrons + ½(bonding electrons)]. Prefer structures with small
formal charges.
Class 11 Chemistry • Chemical Bonding Page 1
