Ionic Bond Formation

📚 Key Concepts

🔹 Real-Life Example

When you dissolve salt (NaCl) in water, it breaks into sodium ions (Na⁺) and chloride ions (Cl⁻). These charged particles are what make salt water conduct electricity – which is why you should never use electrical appliances near salt water! The formation of these ions happens when sodium (a metal) transfers its electron to chlorine (a non-metal).

Ionic Bond: The electrostatic force of attraction between oppositely charged ions formed by complete transfer of electrons from metal atoms to non-metal atoms.

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🧪 Formation Process

🔸 Why Ionic Bonds Form

  • Metals: Have 1-3 electrons in outermost shell → tend to lose electrons
  • Non-metals: Have 5-7 electrons in outermost shell → tend to gain electrons
  • Goal: Both achieve stable electronic configuration (like nearest noble gas)

🔸 Examples of Formation

1. Sodium Chloride (NaCl)

  • Sodium: Na (2,8,1) → Na⁺ (2,8) + e⁻
  • Chlorine: Cl (2,8,7) + e⁻ → Cl⁻ (2,8,8)
  • Result: Na⁺ + Cl⁻ → NaCl (ionic compound)

2. Magnesium Chloride (MgCl₂)

  • Magnesium: Mg (2,8,2) → Mg²⁺ (2,8) + 2e⁻
  • Chlorine: 2Cl (2,8,7) + 2e⁻ → 2Cl⁻ (2,8,8)
  • Result: Mg²⁺ + 2Cl⁻ → MgCl₂

3. Calcium Oxide (CaO)

  • Calcium: Ca (2,8,8,2) → Ca²⁺ (2,8,8) + 2e⁻
  • Oxygen: O (2,6) + 2e⁻ → O²⁻ (2,8)
  • Result: Ca²⁺ + O²⁻ → CaO

🔍 Properties of Ionic Compounds

🔸 Physical Properties

  1. Hard and Brittle: Strong ionic bonds, but shatter when force applied
  2. High Melting/Boiling Points: Need lots of energy to break ionic bonds
  3. Soluble in Water: Water molecules surround and separate ions
  4. Conduct Electricity:
    • Solid state: No (ions fixed in position)
    • Molten/Solution: Yes (ions can move freely)

🔸 Real-Life Applications

  • Table salt: Food seasoning, food preservation
  • Calcium fluoride: Toothpaste (prevents tooth decay)
  • Sodium bicarbonate: Baking soda, antacid
  • Potassium nitrate: Fertilizers, gunpowder