IGCSE · Practice questions · The reactivity series

Rank the metals.

Six original Cambridge-style questions on the reactivity series and displacement reactions.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.

Keep these straight

Higher displaces lower.

Order: K, Na, Ca, Mg, Al, (C), Zn, Fe, (H), Cu, Ag, Au.
Displacement: a more reactive metal pushes out a less reactive one.
Extended: more reactive = forms positive ions more readily.
Aluminium: protected by its oxide layer.

Analysis

[3 marks]

Metals W, X and Y are added to dilute hydrochloric acid. W fizzes rapidly, X does not react, and Y fizzes slowly. Put them in order of reactivity, most reactive first, and suggest which could be copper.

W, Y, X. ✓
X could be copper (no reaction with dilute acid). ✓
(W could be magnesium; Y could be iron or zinc.) ✓

Recall

[3 marks]

Zinc is added to copper(II) sulfate solution. Describe two observations and write the word equation.

The blue colour of the solution fades. ✓
A pink-brown solid (copper) forms on the zinc (and the mixture gets warm). ✓
zinc + copper(II) sulfate → zinc sulfate + copper ✓

Analysis

[2 marks]

Predict whether a reaction occurs, and name any products: (a) iron + silver nitrate solution, (b) copper + magnesium sulfate solution.

(a) yes: iron nitrate and silver. ✓
(b) no reaction: copper is less reactive than magnesium. ✓

Recall

[2 marks]

(Extended) Write the ionic equation for the reaction of iron with copper(II) sulfate solution to form iron(II) ions.

Fe(s) + Cu²⁺(aq) → Fe²⁺(aq) + Cu(s) ✓
One mark for the species, one for balancing and state symbols. ✓

Explain

[2 marks]

(Extended) Explain, in terms of electrons, why zinc displaces copper from copper(II) sulfate solution.

Zinc is more reactive, so it loses electrons more readily than copper. ✓
Zinc atoms give electrons to Cu²⁺ ions, forming Zn²⁺ ions and copper atoms. ✓

Explain

[2 marks]

Explain why aluminium saucepans do not react with water although aluminium is a reactive metal.

The surface of aluminium is covered by a thin layer of aluminium oxide. ✓
This layer is unreactive and stops water reaching the metal. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.