• 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 functional group and is what allows alkenes to react in ways that alkanes cannot
• Alkenes?have the general molecular formula?CnH2n
• They are said to be?unsaturated hydrocarbons
  • They contain carbon-carbon double bonds
  • They are made up of hydrogen and carbon atoms only
• Alkenes are named using the nomenclature rule?alk + ene
• In molecules with a straight chain of 4 or more carbon atoms, the position of the C=C double bond must be specified
• The carbon atoms on the straight chain must be numbered, starting with the end closest to the double bond
• The lowest-numbered carbon atom participating in the double bond is indicated just before the -ene:

The First Five Members of the Alkene Family