Functional groups and homologous series

• A functional group is an atom or group of atoms responsible for the typical chemical reactions of a molecule.

Functional groups and homologous series

• A homologous series is a group of molecules with the same functional group but a different number of –CH2 groups.

• Functional groups determine the pattern of reactivity of a homologous series, whereas the carbon chain length determines physical properties such as melting/boiling points.

Homologous series and general formulae

• The general formula of a homologous series can be used to calculate the molecular formula of any member of the series by substituting n for the number of carbon atoms.

Homologous series and general formulae

• For example, the general formula of a halogenoalkane is C_nH_2n+1X, where X is a halogen.