What are aldehydes and ketones characterized by?

Aldehydes and ketones are characterized by the presence of a carbonyl functional group, which consists of a carbon atom double-bonded to an oxygen atom (C=O).

In aldehydes, this carbonyl group is located at the end of the carbon chain, making them terminal functional groups. This configuration allows for unique chemical reactivity compared to other functional groups. In contrast, ketones have the carbonyl group situated within the carbon chain, specifically between two carbon atoms, which gives them different reactivity patterns and properties.

Understanding the structure and position of the carbonyl group is crucial because it dictates the chemical behavior of aldehydes and ketones, influencing how they participate in reactions such as oxidation and reduction. The distinct properties of these compounds are due to the specific nature of the carbonyl group, rather than the presence of other functional groups such as amines or hydroxyls.