# How does geometric isomerism arise?

That answer dealt with optical isomerism only. Structural isomerism deals with connectivity; geometric isomers have the same connectivity, but different geometry. The best example of this principle is $\text{cis"-"2-butene}$ versus $\text{trans"-"2-butene}$, where each isomer certainly possesses the SAME connectivity, $C 1$ connects to $C 2$ connects to .........$C 4$, but geometric isomerism is possible due to the orientation of the methyl groups about the olefinic bond.