• Carbonyl?is the collective name for compounds containing the functional group?C=O
• The general formula of a carbonyl is?C_nH_2nO
• The two sub-families of?carbonyls?are?aldehyde?and?ketone?(known in some countries as alkanals and alkanones)

Aldehydes

• If the carbonyl group is on the end of a chain then it is an?aldehyde?and has the functional group formula,?RCHO
  • the H is written before the O so as not to confuse it with an alcohol
• The nomenclature of?carbonyls?follows the pattern?alkan + al
• There is no need to use numbers in the name as aldehyde will always be on the number 1 carbon atom

Ketones

• Ketones?have a minimum of three carbons and have the general functional group formula,?RCOR
• The nomenclature of?ketones?follows the pattern?alkan + one
• After butanone, the?carbonyl?group can have?positional isomers, so numbering must be used
  • For example pentan-2-one and pentan-3-one

Aldehyde and Ketone Examples Table

• As they have a very similar functional group arrangement,?aldehydes?and?ketones?show similar chemical reactions
• Differences in their chemistry are due to the reactions that involve the H on the?aldehyde?or the nature of the R group
• The difference in?electronegativity?between oxygen and carbon means the C=O is polar, leading to dipole-dipole attractions between the molecules which results in:
  • higher than expected boiling points for small molecules
  • solubility in water for the lower members of the families
• Aldehydes?and?ketones?with the same number of carbons are?functional group isomers