A-LevelChemistryAtomic structureMay/June 2025Paper 1 Q141 Mark
A helium ion contains two protons, two neutrons and one electron. This helium ion and a proton are passed separately through a uniform electric field. The particles are travelling at the same velocity. Which arrow describes the path of each particle? [Figure showing electric field with '+' and '-' plates and 5 numbered arrows for particle paths]
A[helium ion: 1, proton: 2]
B[helium ion: 2, proton: 1]
C[helium ion: 4, proton: 5]
D[helium ion: 5, proton: 4]
✓ Correct Answer
The correct answer is C: [helium ion: 4, proton: 5]
📋 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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