🧪 NCERT Class XI · Chapter 4

Chemical Bonding & Molecular Structure

Discover how atoms connect to form molecules, crystals and the materials that shape our physical world.

⚛️
3
Bond Types
📐
5+
Molecular Shapes
🧠
VSEPR
Geometry Tool
🎯
High
Exam Weight

Chemical bonding explains how atoms combine to form molecules and solids and how these arrangements determine properties like shape, polarity, melting point and reactivity.

In this chapter you explore why atoms strive for stable electronic configurations and how electron transfer or sharing results in ionic and covalent bonding.

📚 What This Chapter Covers

⚛️ Kössel–Lewis theory explains bonding using noble gas configurations.

🧲 Ionic bonding involves electron transfer and lattice formation.

🤝 Covalent bonding occurs through sharing of electron pairs.

📐 VSEPR theory predicts molecular geometry.

🔷 Hybridisation explains equivalent bonds and bond angles.

🧪 Molecular orbital theory explains bond order and magnetism.

💡 Key Relations

🧮 Bond Order
Bond order = (Nb − Na) / 2

Higher bond order indicates stronger and shorter bonds.

📐 Steric Number
Steric number = σ bonds + lone pairs

Used to predict molecular shape in VSEPR theory.

⚡ Dipole Moment
μ = δ × d

Determines polarity of molecules.

🎯 Key Takeaways

⚛️ Octet rule explains stability of many molecules.
🧂 Ionic solids form strong crystalline lattices.
🤝 Covalent bonds arise from electron sharing.
📐 VSEPR predicts molecular geometry.
🔷 Hybridisation explains equivalent bonds.
🧲 MO theory explains paramagnetism of O₂.

📚 Study Resources

🟢
NCERT Solutions
Step-by-step solutions for textbook exercises.
🧮
NCERT Solutions
Step-by-step solutions for textbook exercises.
🏆
Previous Year Questions
JEE & NEET questions from past papers.

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