A-LevelChemistryChemical periodicityOct/Nov 2017Paper 2 Q315 Marks
The elements in Group 2 show trends in their properties that are typical of metals. The elements in Group 17 show trends in their properties that are typical of non-metals. Some reactions based on the Group 2 metal barium, Ba, are shown. [Figure showing reaction scheme: Ba(NO3)2(aq) + H2(g) (reaction 1) → Ba(s) (reaction 2) → Ba(OH)2(aq) + H2(g); also Ba(s) (heat in air) → X(s)]
📋 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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