Alkanes do not have a double bond, thus they are saturated. This makes them the simplest form of hydrocarbon, containing only hydrogen and carbon atoms. They are not very reactive as they don't have a double bond which can open up and join on to other molecules.
A related group of hydrocarbons is called the alkynes. These are unsaturated hydrocarbons that possess one or more triple-carbon bonds. They follow the same naming rule as the alkanes.
