How do you denote a ketone in IUPAC nomenclature?

In IUPAC nomenclature, ketones are specifically identified using the suffix -one. Ketones are a class of organic compounds characterized by the presence of a carbonyl group (C=O) bonded to two other carbon atoms. This structure is essential in distinguishing them from other functional groups like aldehydes and alcohols.

When naming a ketone, the longest carbon chain that contains the carbonyl group is identified, and the position of the carbonyl group is indicated by the number of the carbon atom to which it is attached. The naming culminates with the suffix -one to signal that the compound is indeed a ketone. For instance, in a molecule like 2-pentanone, the '2' indicates the position of the carbonyl group attached to the second carbon in a five-carbon chain.

In contrast, the suffix -al designates aldehydes, -oid is not used in standard IUPAC nomenclature for any functional group you would encounter here, and -ene is used for alkenes, which contain double bonds but lack the carbonyl functional group characteristic of ketones. Thus, -one is distinctly the appropriate suffix for naming ketones.