Alkenes have at least one double bond in their structure.
The general formula is C(n)H(2n).
They are unsaturated.
When naming, specify the positional number of the beginning of the double bond. Try to assign the lowest numbers to the double bond. Alkenes get priority over alkynes.
If there is more than one double bond, use di-, tri-, etc.
Alkenes end in -ene suffix.
Naming: double and then triple bonds get priority over alkyl and halogen groups.
Alkenes and cycloalkanes can have cis- (same side) and trans- (opposite sides) descriptors. Cis- and trans- are specified at the beginning of the name.
Alkenes may be cyclic.
Nonpolar. London forces are additive. When comparing, size comes first then packing efficiency.
The benzene ring (aromatic) is a special case of a cyclical alkene where the cyclohexene alternates between double and single bonds all the way around the ring. This special structure has resonance and the aromatics have a category all of their own.
