MO9

Question 1

Define what makes something an aromatic compound

Answer 1

• historically defined by smell
• aromaticity occurs in a cyclic structure when:
  1. It is planar with an uninterrupted conjugate electron system
  2. The ring has an odd number of pairs of shared electrons
• huckel 4n + 2 rule: an unsaturated cyclic compound is aromatic when it has (4n + 2) shared (pi) electrons in the ring system

Question 2

Define what a heterocycle and a heteroatom is

Answer 2

• A cyclic compound with carbon and at least one other atom in the ring system (usually a N, O or S)
• a heteroatom is any atom that is not C or H

Question 3

Define what a heterocycle and a heteroatom is