Nomenclature of Alkanes

Naming alkanes for organic chemistry. These are ur basic rules you must know by heart

An alkane

A hydrocarbon (made only of carbon and hydrogen) where all carbon-carbon bonds are single bonds. They are "saturated"

What is the general formula for a straight-chain alkane?

Cn​H2n+2​ (where 'n' is the number of carbon atoms).

hat is the prefix for 1 carbon atom in an alkane name?

Meth- (e.g., Methane)

What is the prefix for 2 carbon atoms in an alkane name?

Eth- (e.g., Ethane)

What is the prefix for 3 carbon atoms in an alkane name?

Prop- (e.g., Propane)

What is the prefix for 4 carbon atoms in an alkane name?

But- (e.g., Butane)

What is the prefix for 5 carbon atoms in an alkane name?

Pent- (e.g., Pentane)

What is the prefix for 6 carbon atoms in an alkane name?

• Hex- (e.g., Hexane)

What is the prefix for 7 carbon atoms in an alkane name?

Hept- (e.g., Heptane)

What is the prefix for 8 carbon atoms in an alkane name?

Oct- (e.g., Octane)

What is the prefix for 9 carbon atoms in an alkane name?

• Non- (e.g., Nonane)

What is the prefix for 10 carbon atoms in an alkane name?

Dec- (e.g., Decane)

What is the first step in naming a branched alkane?

Find the longest continuous carbon chain. This chain is your "parent chain" and gives the base name of the alkane.

• What is the second step in naming a branched alkane, after finding the parent chain?

Number the parent chain from the end that gives the substituents (branches) the lowest numbers.

What do you call the groups attached to the parent chain in a branched alkane?

Substituents or alkyl groups.

How do you name an alkyl group? (e.g., a one-carbon branch, a two-carbon branch)

Change the '-ane' ending of the corresponding alkane to '-yl'.

• Methane → methyl (CH3-)

• Ethane → ethyl (CH3CH2-)

• Propane → propyl (CH3CH2CH2-)

CH3CH2-

Ethyl

CH3CH2CH2

Propyl

(CH3)2CH

Isopropyl

CH3CH2CH2CH2

Butyl

(CH3)2

Iso

(CH3)2CHCH2

isobutyl

CH3CH2CHCH2

sec-butyl

(Ch3)3C-

tert-butyl

What if you have multiple identical alkyl groups (e.g., two methyl groups)? How do you show that in the name?

Use prefixes: di- (for two), tri- (for three), tetra- (for four), etc., before the alkyl group name. (e.g., dimethyl,

How do you list different substituents in the final name?

List them in alphabetical order. (Ignore prefixes like di-, tri-, etc., when alphabetizing, but do count iso-, neo-, cyclo- etc. if they are part of the base name of the substituent.)

What do you use to separate numbers from numbers in a name? What about numbers from letters?

• Numbers from numbers: Commas (,)

• Numbers from letters: Hyphens (-)