AQA A-Level Chemistry Paper 3, 2021: Question 12

1 mark · Easy difficulty · Multiple Choice

Inorganic Ionic Compounds – Properties and Misconceptions This multiple-choice question tests students’ understanding of general properties of ionic compounds, particularly what is always true about them. It assesses knowledge of structure (giant lattice), ion types (metal cations), and typical behaviour in solution and upon melting. It challenges students to distinguish between common trends and absolute rules.

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Question

Question text

12 Which statement about inorganic ionic compounds is always correct?

[1 mark]

A They dissolve in water to give neutral solutions.

B They release energy when they melt.

C They contain metal cations.

D They form giant structures.

Mark scheme

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12 D 1 They form giant structures.

How to answer it

MCQ Analysis: Inorganic Ionic Compounds

Correct answer: D

D: They form giant structures.
Ionic compounds consist of a vast lattice of alternating positive and negative ions. This repeating pattern makes them giant ionic structures, and it is a fundamental property of all such compounds.

A: They dissolve in water to give neutral solutions.
This is not always true. Some ionic compounds (like ammonium chloride) form acidic solutions, and others (like sodium carbonate) can form alkaline ones.

B: They release energy when they melt.
This is incorrect. Energy must be supplied (not released) to overcome the strong electrostatic forces between ions, so melting is an endothermic process.

C: They contain metal cations.
Many ionic compounds contain metal cations, but not always. For example, ammonium salts (like NH₄Cl) are ionic but contain a non-metal cation (NH₄⁺).

Topics

Physical Chemistry · 3.1.3 Bonding

Question and mark scheme from the AQA A-Level Chemistry examination, Paper 3, 2021. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.