A-LevelChemistryChemical bondingMay/June 2013Paper 1 Q91 Mark

Dicarbon monoxide, C₂O, is found in dust clouds in space. Analysis of it shows that the sequence of atoms in this molecule is C–C–O. All bonds are double bonds and there are no unpaired electrons. How many lone pairs of electrons are present in a molecule of C₂O?

Q: What topic does this question test?

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

✓ Correct Answer

The correct answer is C: 3

📋 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 bonding in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry May/June 2013 examination, Paper 1 Variant 2.

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