Article / Updated 07-16-2021
When naming a branched alkane, after you locate and number the parent (longest) chain, you need to locate and identify all the substituents that stick off of the parent chain, and then order the substituents alphabetically in front of the parent chain.
Locate and identify the substituents in a branched alkane
For example, say you have a heptane molecule with two substituents coming off the parent chain — one substituent at carbon number three, and one substituent at carbon number four, as shown here.