The position number and name of the alkyl group are in front of the double-
bond position number. The alkyl group above is an ethyl group. It is on the second
carbon atom of the parent hydrocarbon.
The name is: 2-ethyl-1-pentene
If the double bond occurs on an interior carbon, the chain is numbered so that
the position of the double bond is designated by the lowest possible number
assigned to the first doubly bonded carbon. For example:
The bonding is more complex in the double covalent bond than in the single
bonds in the molecule. Using the orbital pictures of the atom, we can show this as
follows:
The two p lobes attached above and below constitute one bond called a pi
(π) bond.
The sp^2 orbital bonds between the carbons and with each hydrogen are
referred to as sigma (σ) bonds.
TIP
Alkynes have the form CnH 2 n (^) − 2.
Alkyne Series (Unsaturated)
The alkyne series has a triple covalent bond between two adjacent carbons. The