Monomer: GCSE Chemistry Definition

What is a monomer?

In GCSE Chemistry, a monomer is a small reactive molecule. Monomers join with other monomers to form a large molecule called a polymer. Polymers are created by addition reactions and condensation reactions.

What are addition polymers?

Addition polymers are formed from monomers containing carbon-carbon double bonds (C=C). For instance, ethene molecules can undergo a reaction to produce poly(ethene). During this process, one of the bonds in the C=C double bond breaks, enabling the monomers to join together. The resulting polymer consists solely of single bonds between the carbon atoms.

What are condensation polymers?

Condensation polymers are formed from monomers such as:

• dicarboxylic acids and diols

• dicarboxylic acids and diamines

• amino acids

These monomers contain two functional groups, one at each end. The functional group of one monomer reacts with the functional group of another. This reaction results in the elimination of a small molecule, typically water.

Key Difference:

• Addition polymers involve breaking a double bond in a single type of monomer.

• Condensation polymers involve the reaction of molecules containing different functional groups and the removal of a small molecule like water.

Monomer Revision Resources to Ace Your Exams

To explore monomers further, you should check out the revision notes on monomers and polymers and practise our exam questions to ensure success. Flash cards on monomers and polymers are also a great way to revise the wider topic of equilibrium before an exam. 

Explore our GCSE Chemistry revision resources.