A-LevelChemistryChemical periodicity9701/12 · Oct/Nov 2025 · Q171 Mark

Sodium and sulfur react together to form sodium sulfide, Na2S. How do the atomic radius and ionic radius of sodium compare with those of sulfur?

Asulfur is greater, sodium is greater

Bsulfur is greater, sulfur is greater

Csodium is greater, sodium is greater

Dsodium is greater, sulfur is greater

✓ Correct answer

D: sodium is greater, sulfur is greater

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Topic: Chemical periodicity, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, Oct/Nov 2025 Paper 1 Variant 2, question 17.

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