Which teacher is best for Chemistry?

The one who makes a student reason rather than memorise. Chemistry is where memorisation quietly stops working, usually around Grade 11 — Organic Chemistry has far too many reactions to hold as a list, so a student taught to recall rather than to reason runs out of room. Look for a teacher who asks why a reaction goes the way it does, who enforces units and significant figures in numerical work, and who marks against the board your child will actually sit.