Aldehydes and ketones have:

Aldehydes and ketones have Carbonyl group (C=O) in common.

Properties of Aldehydes and ketones

• In a ketone, two carbon groups are attached to the carbonyl carbon atom.
• In an aldehyde, at least one of the attached groups must be a hydrogen atom.
• Generally, ketones’ common names consist of the names of the groups attached to the carbonyl group, followed by the word ketone.
• In both aldehydes and ketones, the carbon atom’s geometry in the carbonyl group is trigonal planar; the carbon atom exhibits sp² hybridization.
• Many of the reactions of aldehydes and ketones start with the reaction between a Lewis base and the carbon atom at the positive end of the polar C=O bond to yield an unstable intermediate
• The oxidation of alcohols commonly prepares aldehydes. Dimethyl ketone, CH₃COCH₃, commonly called acetone, is the simplest ketone.
• Formaldehyde, an aldehyde with the formula HCHO, is the simplest aldehyde