Final answer:
The first member of the ketone series is named propanone according to IUPAC nomenclature, which is commonly known as acetone or dimethyl ketone.
Step-by-step explanation:
The IUPAC name of the first member of the ketone series is propanone. According to the IUPAC rules for naming ketones, the name is derived from dropping the '-e' from the name of the longest continuous chain (LCC) alkane containing the functional group, and adding the ending '-one'. Thus, for a three-carbon ketone, the base name is 'propane', and upon replacing the '-e' with '-one', we get 'propanone', which is the IUPAC name for acetone, also known as dimethyl ketone.