Summary Unit 14 C Applications of Organic Chemistry- BTEC Extended diploma applied medical science

P4. Explain the different types of structural isomerism and stereoisomerism.

Isomers are molecules which have the same molecular formula but have different structural or
spatial arrangement of atoms. Due to this, the isomers can have different chemical or physical
properties. There are two main forms of isomerism; structural isomerism and stereoisomerism.

Structural isomerism is any two or more chemical compounds which have the same
molecular formula but different structural formulae. There are different types of structural
isomers. These are; chain, positional and functional group isomerism.

Chain isomerism is the different arrangement of a molecules carbon skeleton. The positioning
of carbon atoms in a molecule can be arranged differently to produce carbon chains which are
branched off of the main chain. To reflect this new rearrangement, the IUPAC name of the
molecule changes, but the molecular formula still remains the same.




Positional isomerism is when the same functional group of a molecule is placed in a different
position. Again, the IUPAC name of the molecule changes to reflect this new position of the
functional group, but the molecular formula still remains the same.