A-LevelChemistryChemical periodicity9701/12 · May/June 2025 · Q221 Mark

Elements Y and Z are both in Period 3. Element Y has the smallest atomic radius in Period 3. There are only two elements in Period 3 that have a lower melting point than element Z. Elements Y and Z react together to form compound R. Which compound could be R?

AMgCl2

BMgS

CNa2S

DPCl3

✓ Correct answer

D: PCl3

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Topic: Chemical periodicity, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, May/June 2025 Paper 1 Variant 2, question 22.

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