Key Functional Groups Every A-Level Student Should Know

When studying organic chemistry, it's super important to understand functional groups. These groups help us know how different compounds act and behave. Here are the main functional groups that A-Level chemistry students should learn:

1. Alcohols

   • Formula: $R-OH$
   • What they are: They have a hydroxyl group (-OH). They mix well with water and can form bonds with hydrogen.
   • Example: Ethanol ($C_2H_5OH$), which is found in drinks like beer and wine.

2. Aldehydes

   • Formula: $R-CHO$
   • What they are: They have a carbonyl group (C=O) at the end of a carbon chain.
   • Example: Formaldehyde ($H_2C=O$), which is used in some cleaning products.

3. Ketones

   • Formula: $R_2C=O$
   • What they are: They have a carbonyl group (C=O) in the middle of the carbon chain.
   • Example: Acetone ($C_3H_6O$), which is found in nail polish remover.

4. Carboxylic Acids

   • Formula: $R-COOH$
   • What they are: They have a carboxyl group (-COOH) and are often sour.
   • Example: Acetic acid ($CH_3COOH$), which makes vinegar taste tangy.

5. Esters

   • Formula: $RCOOR'$
   • What they are: They are made by mixing an alcohol and a carboxylic acid. They often smell fruity.
   • Example: Ethyl acetate ($C_4H_8O_2$), used in some glues and nail polish removers.

6. Amines

   • Formula: $R-NH_2$, $R_2-NH$, or $R_3-N$
   • What they are: They have a nitrogen atom connected to carbon. They can mix with hydrogen and are basic.
   • Example: Methylamine ($CH_3NH_2$), which is used in some chemical reactions.

7. Amides

   • Formula: $R-CONH_2$
   • What they are: They have a carbonyl group (C=O) connected to a nitrogen atom. They are not as basic as amines.
   • Example: Acetamide ($CH_3CONH_2$), used in some pharmaceuticals.

8. Alkenes

   • Formula: $C_nH_{2n}$
   • What they are: They have at least one carbon-carbon double bond (C=C).
   • Example: Ethene ($C_2H_4$), also known as ethylene, is used to make plastics.

9. Alkynes

   • Formula: $C_nH_{2n-2}$
   • What they are: They have at least one carbon-carbon triple bond (C≡C).
   • Example: Ethyne ($C_2H_2$), commonly known as acetylene, used in welding.

By learning these functional groups, A-Level students can better understand how organic molecules will behave. This knowledge is super helpful for tests and real-world chemistry applications!