Reactivity Series – IGCSE Chemistry Definition
IGCSE Chemistry definition of reactivity series: metals ranked by reactivity. Covers the order, reactions, extraction methods, and exam tips for Cambridge 0620.
Published by IGCSEChemistry.com.my
Chemistry teaching team: K. S. Tan (15+ years teaching IGCSE Chemistry) and Ms Yash (10+ years teaching IGCSE Chemistry) and Ms Kartini (15+ years teaching IGCSE Chemistry).
Mapped to Cambridge IGCSE Chemistry 0620 (2026–2028). Last updated 2026-08-19.
The reactivity series is the backbone of the metals topic. It determines which metals can be extracted by carbon reduction, which displace others from solution, and which corrode. At least 5–8 marks per paper depend on knowing this order.
The 0620 definition
The reactivity series is a list of metals (and carbon and hydrogen) arranged in order of their reactivity, from most reactive to least reactive.
The order you must memorise
| Position | Element | Reaction with water | Reaction with dilute acid |
|---|---|---|---|
| K | Potassium | Violent | Too dangerous |
| Na | Sodium | Vigorous | Too dangerous |
| Ca | Calcium | Steady | Vigorous |
| Mg | Magnesium | Very slow (steam: vigorous) | Vigorous |
| Al | Aluminium | No reaction (oxide layer) | Slow (once oxide removed) |
| (C) | Carbon | — | — |
| Zn | Zinc | No reaction | Moderate |
| Fe | Iron | No reaction (steam: slow) | Slow |
| (H) | Hydrogen | — | — |
| Cu | Copper | No reaction | No reaction |
| Ag | Silver | No reaction | No reaction |
| Au | Gold | No reaction | No reaction |
Why carbon and hydrogen are included
- Carbon: metals above carbon in the series cannot be extracted by carbon reduction — they need electrolysis. Metals below carbon can be extracted by heating their oxide with carbon (e.g. in a blast furnace).
- Hydrogen: metals above hydrogen react with dilute acids to produce hydrogen gas. Metals below hydrogen (Cu, Ag, Au) do not react with dilute acids.
Linking reactivity to extraction
| Metal position | Extraction method | Example |
|---|---|---|
| Above carbon (K → Al) | Electrolysis | Aluminium from bauxite |
| Below carbon, above hydrogen (Zn, Fe) | Reduction with carbon/CO | Iron in the blast furnace |
| Below hydrogen (Cu, Ag, Au) | Found native or easily reduced | Gold panning |
Worked exam question
Magnesium is placed in zinc sulfate solution. (a) State what you would observe. [1] (b) Write the equation. [1] (c) Explain why this reaction occurs. [1]
Mark scheme
(a) A grey/dark solid forms (on the magnesium) / the solution becomes colourless [1]
(b) Mg(s) + ZnSO₄(aq) → MgSO₄(aq) + Zn(s) [1]
(c) Magnesium is more reactive than zinc / higher in the reactivity series [1]
Common exam mistakes
- Putting aluminium below carbon — aluminium is above carbon in the reactivity series. Although it reacts slowly due to its oxide layer, it is still very reactive.
- Saying copper reacts with dilute acid — copper is below hydrogen, so it produces no reaction.
- Forgetting that the reactivity series predicts extraction method — this link is frequently tested.
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