Consider a cyclohexane molecule with two substituents: a bromine atom located at the 1-position and an ethyl group at the 3-position. How would you correctly name this compound following IUPAC conventions?

The correct IUPAC name is 1‑bromo‑3‑ethylcyclohexane. First, choose a numbering that gives the lowest possible locants for the substituents; starting at the bromine gives locants 1 and 3, which is lower than the alternative 1 and 4 that would arise if you started at the ethyl group. The prefix “bromo” comes before “ethyl” because halogens have higher alphabetical priority. Thus the full name is 1‑bromo‑3‑ethylcyclohexane. For example, a molecule with a bromine on carbon 1 and an ethyl group on carbon 3 of the cyclohexane ring is described by that name.