To begin reading molecular structures, divide the molecule into two parts:

• The functional group, which consists of heteroatoms and/or multiple bonds; symbolized G

• The rest of the molecule, composed chiefly of carbon and hydrogen; symbolized G

Although there are something like 28 million organic compounds, only about 20 functional groups exist.

• The key idea is that what kind of chemistry a molecule undergoes is determined by the functional group

• The rest of the molecule plays a role in determining, for example, how fast the chemistry occurs

The next steps in reading the structure will come as we consider more and more elements of structure, and will be added below.