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Learn4CH1Paper 2C · Paper 2 (all content)Inorganic chemistryReactivity series
Inorganic chemistry · Subtopic 7 of 14

The Reactivity Series

The reactivity series lists metals from most to least reactive: K, Na, Ca, Mg, Al, (C), Zn, Fe, (H), Cu, Ag, Au. More reactive metals form positive ions more easily. Metals above hydrogen react with dilute acids; metals above magnesium react with cold water. A more reactive metal displaces a less reactive one from a solution of its compound, e.g. Zn+CuSO4→ZnSO4+Cu\mathrm{Zn+CuSO_4\rightarrow ZnSO_4+Cu}.

Cambridge 5070 Paper 1Cambridge 5070 Paper 2Cambridge 0620 Papers 2, 4Cambridge 0620 Papers 1, 3Edexcel 4CH1 Paper 1CEdexcel 4CH1 Paper 2C≈ 35 minRevision 1 · updated 2026-10-30
Section 1 of 14

Learning objectives

  • Recall the reactivity series.
  • Describe reactions of metals with water, steam and acids.
  • Predict and explain displacement reactions.
Pause and think

Aluminium is high in the reactivity series, yet aluminium pans don't react with water. Why?

Section 2 of 14

Core idea

Start hereA league table of metals

Potassium bursts into flame in water; gold lies untouched in rivers for millions of years. Ranking metals by reactivity lets you predict reactions you've never seen.

The big idea

The more easily a metal forms positive ions, the more reactive it is. A more reactive metal will take the place of a less reactive one in its compounds.

1. The series

Reactivity series

Carbon and hydrogen are reference points.

Worked exampleOrdering from experiments

Metal A reacts with steam but not cold water. B reacts with neither, nor with dilute acid. C reacts vigorously with cold water.

Goal
Order A, B, C.
Strategy
Most vigorous reaction first.
  1. C>AC>A
    C reacts with cold water; A only with steam.
  2. A>BA>B
    B is below hydrogen (no reaction with acid).
AnswerC > A > B (e.g. sodium, iron, copper).
✓ CheckConsistent with the series ✓.

2. Displacement

Worked exampleSilver from silver nitrate

Copper wire is placed in silver nitrate solution.

Goal
Observations and ionic equation.
Strategy
Copper is above silver.
  1. Cu+2Ag+→Cu2++2Ag\mathrm{Cu+2Ag^+\rightarrow Cu^{2+}+2Ag}
    Copper loses electrons; silver ions gain them.
  2. silver crystals; solution turns blue\text{silver crystals; solution turns blue}
    Cu2+\mathrm{Cu^{2+}} ions are blue.
AnswerGrey silver crystals grow on the wire and the solution turns blue.
✓ Check2 electrons lost, 2 gained ✓.
Edge caseAluminium's disguise Aluminium seems unreactive in many experiments because a thin Al2O3\mathrm{Al_2O_3} layer protects it. Remove the layer and it reacts vigorously.
Pause and think

Why can't you store copper(II) sulfate solution in an iron container?

Summary

  • K Na Ca Mg Al C Zn Fe H Cu Ag Au.
  • Reactivity = ease of forming positive ions.
  • Higher displaces lower.
Key words
Reactivity series
Metals listed in order of reactivity.
Displacement
A more reactive metal replaces a less reactive one in a compound.
Native metal
A metal found uncombined in nature.
HistoryThermite welding. Since 1899, railway lines have been welded with the thermite reaction: aluminium displaces iron from iron oxide so violently that the iron comes out molten.
Fun factGold never tarnishes. Tutankhamun's gold mask looked as bright when it was found in 1922 as it did 3300 years earlier. Gold is so unreactive it doesn't corrode.
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