One of the structural isomers has a geometric isomer.
"1. cyclobutane"1. cyclobutane; "2. methylcyclopropane"2. methylcyclopropane; "3. 1-butylene"3. 1-butylene; "4. 2-butylene"4. 2-butylene; "5. 2-methylpropene"5. 2-methylpropene.
"2-butylene"2-butylene can of course generate 2 geometric isomers, which are?
Just to add a bit more method to the analysis. It is a fact that an alkane has general formula C_nH_(2n+2)CnH2n+2. In this analysis, an halide counts for HH, oxygens are ignored (they can be carbonyls or alcohols or ethers), and if there is a NN in the compound, we subtract NHNH from the given formula. Each 2 hydrogens less than this formula corresponds to a degree of unsaturation. A degree of unsaturation corresponds to an olefinic bond, OR a ring junction. Thus I knew that the possible isomers of C_4H_8C4H8 were olefins, OR "3- or 4-membered rings"3- or 4-membered rings.
