Here's why:

* Octane has eight carbon atoms (octo means eight).

* Alkanes are hydrocarbons with only single bonds between carbon atoms.

* Linear alkanes have all their carbon atoms connected in a straight chain. Octane can exist in a linear form, but it's not the most stable configuration.

The most common form of octane is isooctane, which has a branched structure. This branched structure makes it a more stable molecule and a better fuel than the linear form.

Let me know if you have any other questions about alkanes or hydrocarbons!