Organic compounds are organized into families. The members of the simplest hydrocarbon family are referred to as alkanes and have only singly bonded carbon.
RH
alkane
R is a hydrocarbon group (such as CH3, CH3CH2 ... )
Other hydrocarbon families have at least one pair of carbons joined by a multiple bond. This is the reactive site in the molecule and is known as the functional group.
R2C=CR2
alkene
The general formula of members of other families where the functional groups have atoms other than C and H are shown below.
Note:
The carbonyl group (C=O) is a common structural element.
R may be H for carbon-containing functional groups
RH
alkane
R is a hydrocarbon group (such as CH3, CH3CH2 ... )
Other hydrocarbon families have at least one pair of carbons joined by a multiple bond. This is the reactive site in the molecule and is known as the functional group.
R2C=CR2
alkene
The general formula of members of other families where the functional groups have atoms other than C and H are shown below.
Note:
The carbonyl group (C=O) is a common structural element.
R may be H for carbon-containing functional groups
| R–X X=Cl, Br, I haloalkane |  (RCOR) ketone |  (RCO2H) carboxylic acid |
| R–OH alcohol |  (RCHO) aldehyde | |
| R–NH2 amine | ||
| . | ||