What are the types of compounds or functional groups that make up 1,4-dichloropent-2-ene?

Answer 1

The easiest way to do this is to look at the parent name of the molecule (i.e., the suffix in the name of the molecule), and the substituents.

We know that the longest, continuous carbon chain in this molecule has 5 carbons (because of the prefix pent-, which means 5)

We also know that this molecule is an alkene (because of the -ene suffix). The location of the double bond is between carbons 2 and 3 (we only list the lowest numbered carbon atom that participates in the double bond).

We know this molecule has 2 substituents; a chlorine atom bonded to carbon 1, and a chlorine atom bonded to carbon 4 (dichloro means 2 chlorines, 1 and 4 indicate where the chlorine atoms are positioned on the parent chain).

You have 2 alkyl halide functional groups (a halogen bonded to a carbon chain) and the compound type is an alkene.