Flexi Says: The smallest hydrocarbon that has isomers is butane, which has just four carbon atoms. The molecular formula of n-butane is C4H10 and it has only one isomer, named iso-butane. Both molecules have four carbon atoms as well as ten hydrogen atoms (C4H10), but the atoms are arranged differently in the two compounds. In n-butane, all four carbon atoms are lined up in a straight chain. In iso-butane, one of the carbon atoms branches off from the main chain.
