Q.Explain the terms polymer and monomer.

Polymer: A polymer is a large (high molecular mass) molecule built up by the repetitive linking, through covalent bonds, of a large number of small repeating structural units. The word comes from Greek poly (many) + mer (unit/part). Example: polythene, $-[-CH_2-CH_2-]_n-$.

Monomer: A monomer is the small, simple molecule (usually containing a reactive double/triple bond or two or more reactive functional groups) that combines repeatedly with itself or with another monomer to build the polymer chain, through the process of polymerisation. Example: ethene ($CH_2=CH_2$) is the monomer of polythene.

In short, many monomer units → (polymerisation) → one polymer molecule.

State the definition of each term precisely, note the covalent-bond linkage and repetitive nature for a polymer, and support both definitions with the ethene/polythene example.

• Giving vague definitions without mentioning 'repeating units' or 'covalent bonds'.
• Confusing which is the small unit (monomer) and which is the large final molecule (polymer).
• Omitting a supporting example.