They can be part of the same or different homologous series, e.g. alkenes and cycloalkanes ... Both have a molecular formula of \({C_4}{H_{10}}\). The structural formulae are different though ...

The table shows the first four alkenes, their molecular formulae, displayed formulae, structural formulae as well as a drawing of their ball-and-stick constructional models.

The rapid disappearance of the amber color of the bromine at room temperature is characteristic of reaction with alkenes. (colorless) (purple) (colorless ...