This document discusses aldehydes and ketones. Aldehydes contain a carbonyl group bonded to a hydrogen atom, while ketones contain a carbonyl group bonded between two carbon groups. The document provides IUPAC and common naming conventions for aldehydes and ketones. Examples are given of aldehydes and ketones that provide flavors or act as hormones. Learning checks provide practice identifying and naming aldehydes and ketones, as well as drawing their structural formulas.