Organic compounds that have the same molecular formula but different structural formulas are called isomers. Isomerism can be classified into four main types: chain isomerism which is a difference in carbon chain, functional group isomerism due to differences in functional groups, position isomerism when functional groups are in different positions of the same carbon chain, and metamerism which is a difference in the number of carbon atoms on either side of a functional group. Examples are provided to illustrate each type of isomerism.

3. Presented by,
Simi
Physical Science

4. Organic compounds with
same molecular formula
but having different
structural formula are
called isomers and the
phenomenon is called
isomerism.

5.  Based on the differences in the structures
isomerism can be classified into various
types.
 Chain Isomerism
 Functional group Isomerism
 Position Isomerism
 Metamerism

6. Chain isomerism occurs due to the
difference in the carbon chain.
Examples for Chain
Isomerism
 BUTANE
CH3- CH2- CH2- CH3
 2-METHYL PROPANE CH3-
CH- CH2- CH3
CH3

7. Functional group isomerism
occurs due to the difference in
functional group.
EXAMPLES
• ETHANOL
CH3- CH2- OH
• DIMETHYL ETHER
CH3- O- CH3

8. Position isomerism occurs when isomers
differ in the position of the functional groups
in the same carbon chain.
EXAMPLES
o 1-BUTANOL
CH3-CH2-CH2-CH2-OH
o 2-BUTANOL
CH3-CH-CH2-CH3
OH

9. Metamerism occurs due to the
difference in the number of carbon
atoms in the alkyl groups on either sides
of a functional group.
EXAMPLES
 ETHOXY BUTANE
CH3-CH2-O-CH2-CH2-CH2-CH3
 METHOXY PENTANE
CH3-O-CH2-CH2-CH2-CH2-CH3