A-LevelChemistryAtomic structureOct/Nov 2012Paper 1 Q21 Mark
Use of the Data Booklet is relevant to this question. The 68Ge isotope is medically useful because it undergoes a natural radioactive process to give a gallium isotope, 68Ga, which can be used to detect tumours. This transformation of 68Ge occurs when an electron enters the nucleus, changing a proton into a neutron. Which statement about the composition of an atom of the 68Ga isotope is correct?
AIt has 4 electrons in its outer p subshell.
BIt has 13 electrons in its outer shell.
CIt has 37 neutrons.
DIts proton number is 32.
✓ Correct Answer
The correct answer is C: It has 37 neutrons.
📋 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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