So remember that an alkyl halide is just an alkyl group connected to a halogen. Here we're going to say that halogens attached to a carbon chain are named as substituents. Fluorine as a substituent is called fluoro, Chlorine is called chloro, Bromine is called bromo, iodine is called iodo.

In terms of our naming convention, they're acting as substituents. So we'd have to give their numerical location in terms of our parent chain, they are substituents with these names and then we have to worry about what is the parent chain, is it a six member chain, is it cyclic, et cetera.

So just remember, when it comes to naming organic compounds, these halogens serve as substituents, and as substituents, they're given these new names.