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A-LevelChemistryChemical periodicityOct/Nov 2018Paper 1 Q121 Mark

The melting points of the Period 3 elements phosphorus to argon are shown in the table. Which factor explains the changes in melting points from phosphorus to argon?

Athe changes in electronegativity from phosphorus to argon
Bthe changes in first ionisation energy from phosphorus to argon
Cthe increase in the number of electrons in each atom from phosphorus to argon
Dthe number of atoms in each molecule of the element from phosphorus to argon

✓ Correct Answer

The correct answer is D: the number of atoms in each molecule of the element from phosphorus to argon

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

🎯 Mark Scheme Breakdown

Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.

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About This A-Level Chemistry Question

Topic

This multiple-choice question tests Chemical periodicity in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry Oct/Nov 2018 examination, Paper 1 Variant 2.

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