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How are aldehydes structurally different from ketones?

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oxidation of alcohols — aldehyde Alcohols may be oxidized to give aldehydes, ketones, and carboxylic acids. The oxidation of organic compounds generally increases the number of bonds from carbon to oxygen, and it may decrease the number of bonds to hydrogen.

Aldehydes and ketones are both carbonyl compounds characterized by a carbon atom double-bonded to an oxygen atom. Their primary structural difference lies in the substituents attached to that carbonyl carbon.12

Aldehydes: The carbonyl carbon is bonded to at least one hydrogen atom. In the simplest aldehyde, formaldehyde, the carbonyl group is bonded to two hydrogen atoms; in all other aldehydes, it is bonded to one hydrogen atom and one carbon group (alkyl or aryl).23
Ketones: The carbonyl carbon is bonded to two other carbon atoms or hydrocarbon radicals.24

Because of this structural distinction, the carbonyl carbon in an aldehyde is always located at the end of a carbon chain, whereas the carbonyl carbon in a ketone is located within the chain, bonded to two other carbons. This difference significantly influences their chemical reactivity, as the hydrogen atom attached to the carbonyl carbon in aldehydes provides distinct reaction pathways not available to ketones.23