1. An Aldehyde has a double bonded Oxygen at the end of the Carbon chain
  2. Ketones have a double bonded Oxygen side group at a position other than the end of the carbon chain.
  3. Ketones have -one at the end of them, eg Butanone
  4. Ethers have an Oxygen in the middle of the carbon chain, eg Methyethylether
  5. An Amine has an NH2 side group. Eg. Amino Ethane.