Chemistry (5070)
Topic 5 of 5Cambridge O Levels

Metals & Reactivity

Properties of metals and the reactivity series

Metals are elements that conduct electricity and heat, are shiny, malleable (can be hammered), and ductile (can be drawn into wires).


Properties of Metals:

  • Good conductors of heat and electricity
  • High melting and boiling points (usually)
  • Malleable and ductile
  • Shiny (lustrous) when polished
  • Sonorous (make a ringing sound when struck)

    • The Reactivity Series (most to least reactive):

    K → Na → Ca → Mg → Al → Zn → Fe → Cu → Ag → Au


    Memory trick: "King Nasir Can't Manage A Zebra In Crazy Silver Gold"


    Reactions with Water:

  • K, Na, Ca: React vigorously with cold water → metal hydroxide + hydrogen
  • Mg: Reacts slowly with cold water, fast with steam
  • Fe: Only reacts with steam
  • Cu, Ag, Au: Don't react with water at all

    • Reactions with Acid:

  • Reactive metals (Mg, Zn, Fe): React with dilute acids → salt + hydrogen
  • Less reactive metals (Cu, Ag, Au): Don't react with dilute acids

    • Displacement: A more reactive metal displaces a less reactive one.

    Fe + CuSO₄ → FeSO₄ + Cu (iron displaces copper because iron is more reactive)


    Extraction of Metals:

  • Very reactive metals (K-Al): Extracted by electrolysis
  • Less reactive metals (Zn-Fe): Extracted by reduction with carbon
  • Unreactive metals (Cu-Au): Found native or by simple heating

    • Key Points to Remember

    • 1Reactivity series: K, Na, Ca, Mg, Al, Zn, Fe, Cu, Ag, Au
    • 2More reactive metals displace less reactive ones from solutions
    • 3Reactive metals extracted by electrolysis, less reactive by carbon reduction
    • 4Gold and silver are unreactive — that's why they don't corrode

    Pakistan Example

    Pakistan Steel Mills & Khewra Salt Mine

    Pakistan Steel Mills in Karachi extracts iron from iron ore (Fe₂O₃) using carbon reduction in blast furnaces: Fe₂O₃ + 3CO → 2Fe + 3CO₂. Iron is below carbon in the reactivity series, so carbon can reduce it. But aluminium (above carbon) can't be extracted this way — it needs electrolysis, which is very expensive. That's why aluminium costs more than steel. The famous Khewra Salt Mine produces NaCl — sodium is too reactive to exist as a free metal, so it's always found as a compound in nature.

    Test Your Knowledge!

    3 questions to check if you understood this topic.

    Start Quiz
    Chemical Reactions & Equations