The IUPAC names of ketones are generated by substituting the final -e of the parent hydrocarbon with -one. In acyclic ketones, the carbonyl carbon is given the lowest possible number, and it precedes the suffix -one, thereby giving the name pentan-3-one. Alternatively, the ketone can also be named with the locant preceding the parent name. In the presence of substituents, the substituent names are prefixed to the parent name along with their locant values. Cyclic ketones are numbered starting from the carbonyl carbon, and the numbering continues in the direction that gives the lowest value to the next substituent on the ring. When the ketone functionality is part of the parent chain comprising other higher priority groups like acids and aldehydes, the parent name is prefixed by the word oxo- along with the locant value. When the ketone functionality is not part of the parent chain, it is named as a substituent, namely, an alkanoyl or an acyl group.