Reactivity Series of Metals

📚 Key Concepts

🔹 Real-Life Example

Ever wondered why gold jewelry never tarnishes while iron rusts quickly? Or why zinc is used to protect iron in galvanization? The reactivity series explains this! It’s like a “popularity contest” for metals – the most reactive metals are at the top (they react with almost everything), while the least reactive “noble metals” at the bottom are so unreactive they remain shiny forever.

Reactivity Series: An arrangement of metals in order of decreasing reactivity. More reactive metals can displace less reactive metals from their salt solutions.

🧪 The Complete Series

Most Reactive → Least Reactive

K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au

Note: Hydrogen (H) is included as a reference point

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🔍 Key Rules

🔸 Displacement Reactions

Rule: More reactive metal displaces less reactive metal from its salt solution

Examples:

  • Iron displaces copper: Fe + CuSO₄ → FeSO₄ + Cu (iron nail becomes copper-coated)
  • Zinc displaces copper: Zn + CuSO₄ → ZnSO₄ + Cu
  • Copper displaces silver: Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag

No Reaction Examples:

  • Silver + Copper sulfate: Ag + CuSO₄ → No reaction (silver less reactive than copper)
  • Gold + Copper sulfate: Au + CuSO₄ → No reaction

🔸 Extraction Methods Based on Reactivity

  1. Most Reactive (K, Na, Ca, Mg, Al)
    • Method: Electrolysis of molten compounds
    • Why: Too reactive for chemical reduction
  2. Medium Reactive (Zn, Fe, Pb, Cu)
    • Method: Chemical reduction (using carbon, CO, or other metals)
    • Example: ZnO + C → Zn + CO
  3. Least Reactive (Hg, Ag, Au)
    • Method: Heat alone or occur naturally
    • Example: 2HgO → 2Hg + O₂