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A-LevelChemistryChemical periodicityFeb/Mar 2021Paper 1 Q131 Mark

Which row is correct? statement reason A The first ionisation energy of phosphorus is greater than that of magnesium. electron is lost from a 3p orbital in both cases B The melting point of phosphorus is greater than that of magnesium. phosphorus has more valence electrons than magnesium C The atomic radius of phosphorus is smaller than that of magnesium. phosphorus has greater nuclear charge than magnesium D The electrical conductivity of phosphorus is smaller than that of magnesium. bonding changes from ionic in magnesium to covalent in phosphorus

AThe first ionisation energy of phosphorus is greater than that of magnesium. electron is lost from a 3p orbital in both cases
BThe melting point of phosphorus is greater than that of magnesium. phosphorus has more valence electrons than magnesium
CThe atomic radius of phosphorus is smaller than that of magnesium. phosphorus has greater nuclear charge than magnesium
DThe electrical conductivity of phosphorus is smaller than that of magnesium. bonding changes from ionic in magnesium to covalent in phosphorus

✓ Correct Answer

The correct answer is C: The atomic radius of phosphorus is smaller than that of magnesium. phosphorus has greater nuclear charge than magnesium

📋 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 Feb/Mar 2021 examination, Paper 1 Variant 2.

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