Period rule for octet expansion
A organic structure seminar compares B and S as possible central atoms for octet expansion. Which atom can expand its octet in the usual IB model? Enter the answer and choose the interpretation that matches the HL chemistry evidence.
Worked practice: chemistry evidence and answer
Use the chemical evidence first, then enter the result and interpretation that match it.
Write a full answer
Now write the response in full, in your own words — this is what the exam asks for. The AI marks it on the same moves you built above (focus, evidence, technique, judgement) and gives feedback on reasoning, evidence, and expression.