- All alkenes contain a double carbon bond, which is shown as two lines between two of the carbon atoms i.e. C=C.
- All alkenes contain a double carbon bond, which is the alkene functional group and is what allows alkenes to react in ways that alkanes cannot.
- The names and structure of the first four alkenes are shown below.
Table showing the formulae and structures of the first four alkanes
- Compounds that have a C=C double bond are also called unsaturated compounds.
- That means they can make more bonds with other atoms by opening up the C=C bond and allowing incoming atoms to form another single bond with each carbon atom of the functional group.
- Each of these carbon atoms now forms 4 single bonds instead of 1 double and 2 single bonds.
- This makes them much more reactive than alkanes.
A carbon carbon double can break and form a single bond, allowing more atoms to attach to the carbon atoms