4.4 understand how to name compounds relevant to this specification using the rules of International Union of Pure and Applied Chemistry (IUPAC) nomenclature

Number of carbons in longest chain	Name
1	Meth
2	Eth
3	Prop
4	But
5	Pent
6	Hex
7	Hept
8	Oct
9	Non
10	Dec

Naming Straight Chain Alkanes:
Alkanes: Simplest hydrocarbon.
e.g. displayed formula for ethane (C₂H₆) is:






- This is called ethane because "eth" means there are 2 carbons in its longest chain, and "ane" means that it is an alkane with single bonds.

Another example is pentane's displayed formula (C₅H₁₂):



- This is called pentane because "pent" means there are 5 carbons in its longest chain, and "ane" means it is an alkane with single bonds.
Pentanes can be drawn differently:

- This is still called a pentane as it has 5 carbons in its longest chain, joined together by single bonds.
They can also be drawn in weird structures with different angled bonds, like this:




However, it is still a pentane as it has 5 carbons with single bonds.

Naming straight chain ALKENES:
Alkenes: C=C double bond
e.g. the displayed formula for ethene (C₂H₄) is:





Propene (C₃H₆):

As you can see, longer chain alkenes can have double bonds at different locations, so a number is added in the middle of the name to indicate at which carbon the double bond starts.
e.g. displayed formula for pent-1-ene is:

 and pent-2-ene is:

HOWEVER! The number is not read in order from left to right. The order in which the number starts is from the end that produces the smallest numbers in the name. For example, this is still pent-1-ene, but drawn with the other way around:



Naming Branched Alkanes and Alkenes:
- branch with 1 carbon: methyl
- branch with 2 carbons: ethyl
This naming is similar to the conventions above, but the "-yl" bit means that there is a branch.
e.g. displayed formula for 2-methyl hexane:

- In the name 2-methyl hexane, number "2" indicates the branch comes off the second carbon atom. "methyl" means there is one branch of 1 carbon. "hex" means the longest chain of carbon atoms is 6. "ane" means it is joined by single bonds (alkane).

More examples:
- 2,2-dimethyl hexane:


- 4-methylpent-1-ene: