Everything Science Grade 12

CHAPTER 1. ORGANICMOLECULES 1.7

H C(1) C(2) C(3) H

H

H

H H

H

C

H

H H

Step 4 : Look for any branchedgroups, name them andgive their posi-

tion on the carbon chain

There is a branched group attached to the second carbon atom.

This group has the formula CH 3 which is methane. However,

because it is not part of the main chain, it is given the suffix -yl

(i.e. methyl). The position of the methyl groupcomes just before

its name (see next step).

Step 5 : Combine the elements of the compound’s name into a single

word in the order of branched groups; prefix; name ending according to

the functional group.

The compound’s nameis 2-methylpropane.

Example 3: Naming the alkanes

QUESTION

Give the IUPAC name for the following compound:

CH 3 CH(CH 3 )CH(CH 3 )CH 3

(Remember that the side groups are shown in brackets after the carbonatom

to which they are attached.)

SOLUTION

Step 1 : Draw the compound from its condensed structural formula

The structural formula of the compound is: