Answer
Using the molecular formula $C_{4}H_{8}$ you can draw isobutylene, butene and trans-butene (see picture). They differ with regards to the position of the C=C double bond. That’s what you have to look at to find a difference. It's because the substituents of the double bond tell you how stable a substance is. The most stable substance of the three is trans-butene followed by isobutylene and butene.
Work Step by Step
To draw the three substances you’ll start by drawing the C=C double bond at different positions. Then you attach the remaining C atoms and H atoms. Keep in mind that carbon atoms usually consist of four bonds while the hydrogen atom just has a single bond.
- As all substances in the picture belong to the alkenes you can make assumptions about the stability of each substance.
- Usually, trans is more stable than cis. Also, take a look at how many hydrogen atoms are attached to the C=C double bond. The fewer hydrogen atoms you can find there the more stable the alkene becomes.
