What type of molecule is 2-methylpentene?

Answer is: branched alkene.

Carbon atoms can be arranged straight chain, branched chain and ring.
Hydrocarbon is an organic compound consisting of hydrogen and carbon.
In straight chain carbon atoms are bonded with only two other carbon atoms in elongate chain.
In branched chain at least one carbon is bonded with more than two other carbon atoms. In this example 2-methylpentene second carbon atom is bonded with three carbon atoms.
Ring chain hydrocarbons are cyclic hydrocarbons.