There is no branching in the molecule. When you are naming an organic compound, you must first begin by determining the longest continuous chain. This is a pentene chain regardless. Then you must determine what substituents are on the pentene chain. There are only hydrogens, hence cis-2-pentene. To draw trans-2-pentene all you would do is simply either exchange the ethyl group with the hydrogen to the left of the double bond or exchange the methyl group with the hydrogen to the right of the double bond. Solution There is no branching in the molecule. When you are naming an organic compound, you must first begin by determining the longest continuous chain. This is a pentene chain regardless. Then you must determine what substituents are on the pentene chain. There are only hydrogens, hence cis-2-pentene. To draw trans-2-pentene all you would do is simply either exchange the ethyl group with the hydrogen to the left of the double bond or exchange the methyl group with the hydrogen to the right of the double bond..