Methane: A carbon atom bonded with 4 hydrogen atoms
Acetylene: A compound with 2 carbon atoms and 2 hydrogen atom. The carbon atoms form triple bonds with each other and single bond with a hydrogen atom.
Butadiene: A compound with a chain of 4 carbon atoms. The carbon atom at each end of the chain form single bonds with 2 hydrogen atoms and a double bond with the next carbon atom. The carbon atoms at the center form a single bond with each other and a hydrogen atom.
Benzene: A compound composed of 6 carbon atoms joined in a ring, with 1 hydrogen atom attached to each atom.