What are amines? Classify them with one example each, and describe the structure of an amine.

1. 1 · Define. Amines are derivatives of ammonia in which one, two or three H atoms are replaced by alkyl or aryl groups.
2. 2 · Classify with examples. Primary RNH₂ (CH₃NH₂), secondary R₂NH ((CH₃)₂NH), tertiary R₃N ((CH₃)₃N).
3. 3 · Describe the structure. N is sp³: three bonds and one lone pair. Shape: pyramidal; the angle is about 108° because the lone pair repels the bond pairs.
4. 4 · Draw it. Draw N at the top of a pyramid with three CH₃ groups below and the lone pair above N. Mark the 108° angle.
5. 5 · Close in one line. So amines are pyramidal like ammonia, and the lone pair on N controls their chemistry.

Scoring tip: Give one example for each class and draw the lone pair on nitrogen; the lone pair is what examiners look for.