What are the most common functional groups in organic chemistry?

The most common functional groups in organic chemistry include: alcohols, amines, carboxylic acids, alkenes, esters, ketones, aldehydes, and ethers. 

• Ketones contain a carbonyl group (C=O) with two alkyl or aryl groups. 
• Carboxylic acids include a carboxyl group (-COOH). 
• Aldehydes are composed of a carbonyl group (C=O) with at least one hydrogen atom attached. 
• Alcohol consists of an oxygen atom linked to both a hydrogen atom.
• Esters are formed from the reaction of a carboxylic acid and an alcohol. 
• Ethers have an oxygen atom bonded to two alkyl or aryl groups. 
• Alkenes include a carbon-carbon triple bond (C≡C).