Hybridization of Atomic Orbitals

Introduction to Hybridization

• Definition: Hybridization is the combination or mixture of atomic orbitals to form new hybrid orbitals.
• Analogy: Similar to mixing salt and water or sugar and water to form a mixture.
• Purpose: To understand molecular geometry and the bonding of atomic orbitals.

Importance of Hybridization

• Molecular Geometry: Shows the shape of molecules.
• Bonding of Atomic Orbitals: Explains how atomic orbitals form bonds.

Why Hybridization Occurs

• To solve the issue of atoms forming different types of bonds with the same atom, making it comprehensible and correct.
• Not all molecules undergo hybridization (e.g., H₂, HCl, H₂S).

Types of Hybridization in Carbon

1. sp³ Hybridization

• Composition: 1 s orbital and 3 p orbitals (total 4 orbitals).
• S and P Character: 25% s character, 75% p character.
• Example: Methane (CH₄).
  • Carbon shares its 4 unpaired electrons with hydrogen, forming sp³ hybridization.
• Geometry: Tetrahedral with a bond angle of 109.5°.
• Orbitals: 4 degenerate sp³ orbitals, each with one electron.

2. sp² Hybridization

• Composition: 1 s orbital and 2 p orbitals (total 3 orbitals).
• S and P Character: 33% s character, 67% p character.
• Example: Ethylene (C₂H₄).
  • Carbon atoms share unpaired electrons in sp² orbitals, forming sigma bonds, and unhybridized p orbitals form pi bonds.
• Geometry: Trigonal with a bond angle of 120°.

3. sp Hybridization

• Composition: 1 s orbital and 1 p orbital (total 2 orbitals).
• S and P Character: 50% s character, 50% p character.
• Example: Acetylene (C₂H₂).
  • Carbon atoms share unpaired electrons in sp orbitals, forming sigma bonds, and unhybridized p orbitals form pi bonds.
• Geometry: Linear with a bond angle of 180°.

Key Concepts

• Hybrid Orbitals: New orbitals formed from the combination of standard atomic orbitals.
• Degenerate Orbitals: Orbitals that have the same energy level.
• Sigma and Pi Bonds: Sigma bonds are formed by overlapping hybrid orbitals, while pi bonds are formed by unhybridized orbitals.
• Energy Considerations: Unhybridized orbitals typically have more energy than hybridized ones.