Chemical Bonding Lecture Notes

Introduction to Chemical Bonding

• Definition: Chemical bonding is the attraction force between atoms, ions, or molecules that forms a chemical compound.
• Examples:
  • Salt (sodium and chlorine)
  • Glucose (carbon, hydrogen, oxygen)
  • Water (hydrogen and oxygen)
• Analogy: Chemical bond is like cement that holds bricks together.

Importance of Chemical Bonding

• Everything in the universe is formed by chemical bonds:
  • Food: Made by chemical bonds.
  • Plants and Animals: Composed of chemical bonds.
  • Materials: Iron, plastic, etc., are made by chemical bonds.

Purpose of Chemical Bonding

• Atoms form chemical bonds to lower their energy and achieve stability.
• Stability Measurement Rules:
  • Dopplet Rule: Stable if two electrons are in the last shell (applicable to hydrogen and helium).
  • Octet Rule: Stable if eight electrons are in the last shell.

Example: Sodium and Chlorine

• Sodium: Has one electron in the last shell.
• Chlorine: Has seven electrons in the last shell.
• Sodium loses one electron and chlorine gains one electron to complete their octet rule, forming a chemical bond.

Conditions for Electron Transfer

• Suitable conditions must exist for atoms to lose or gain electrons; otherwise, no electron transfer occurs.

Types of Chemical Bonding

• Ionic Bonding: Between metals and nonmetals (e.g., sodium chloride).
• Covalent Bonding: Between nonmetals (e.g., water H₂O).
• Metallic Bonding: Between metals (e.g., gold, iron).

Strength of Chemical Bonds

• Covalent Bond: Generally considered the strongest.
  • Example: Diamond (covalent compound) has a high melting point (4027°C).
  • Comparison: Table salt (ionic compound) has a melting point of 801°C.

Additional Resources

• Links to further lectures are provided in the description for more details on chemical bonding.