Alkenes- Are unsaturated (not all single bonds) hydrocarbons (hydrogen and carbon only) containing 1 carbon to carbon double bond "C=C".
The rule for naming is they all end with "-ene".
The general formula is CnH2n, n is the number of carbons is used to determine the number of hydrogen atoms. Example n=5, so H=(2(5))=10
TEST Question-What is the minimum number of carbons that are required to have an alkene?
Since is no such molecule as methene!!! You need at least 2 carbons to have a double bond.
Alkenes are ISOMERs of Cyclic Compounds. They have the same general formula.
Naming Compounds- Again, ignore all the hydrogen's. We only worry about carbon atoms.
Rule #1-Name the longest chain with the double bond. It is not always the longest chain of carbons. End it with "-ene".
Rule #2-When necessary use the lowest number to give the location of double bond in the longest chain.
FYI-2,2-dimethyl propene does not exist