Functional Groups Table
A complete reference for organic chemistry functional groups, structures, and IUPAC naming suffixes.
Alkane
Saturated hydrocarbons with single bonds only. Generally unreactive but undergo combustion and substitution.
Alkene
Unsaturated hydrocarbons with at least one C=C double bond. Reactivity centers on the pi-bond.
Alkyne
Unsaturated hydrocarbons with at least one C≡C triple bond. Linear geometry at the triple bond.
Alcohol
Organic derivatives of water. Polar O-H bond allows for hydrogen bonding, increasing boiling points.
Aldehyde
Contains a carbonyl group (C=O) at the end of the carbon chain. Susceptible to oxidation.
Ketone
Contains a carbonyl group (C=O) within the carbon chain. Polarity makes them excellent solvents.
Carboxylic Acid
Weak organic acids characterized by the presence of a carboxyl group. Capable of strong H-bonding.
Ester
Derived from an acid and an alcohol. Often have pleasant, fruity odors. Polar but no H-bonding.
Ether
Oxygen atom connected to two alkyl or aryl groups. Relatively inert and used as solvents.
Amine
Derivatives of ammonia (NH₃). Act as weak bases due to the lone pair on Nitrogen.
Amide
Derivatives of carboxylic acids where -OH is replaced by -NH₂. Very stable peptide bonds in proteins.
Haloalkane
Alkanes where one or more H atoms are replaced by halogens. Polar C-X bond makes them reactive.
Understanding Structure & Reactivity
In organic chemistry, the Functional Group is the specific part of the molecule that dictates how it behaves in chemical reactions. While the carbon backbone (the "R" group) provides the structure, the functional group provides the "personality" — heavily influencing acidity, polarity, solubility, and reactivity.
Intermolecular Forces (IMF)
Functional groups dramatically affect the physical properties of a compound (like boiling point) by introducing different types of attractive forces between molecules.
London Dispersion Forces
Found in non-polar groups like Alkanes (-H). These are weak, temporary attractions, resulting in low boiling points.
Dipole-Dipole
Found in polar groups like Ketones (C=O) and Aldehydes. The permanent positive and negative ends attract each other.
Hydrogen Bonding
Found in Alcohols (-OH), Acids (-COOH), and Amines (-NH₂). This very strong attraction leads to much higher boiling points and water solubility.
Common Reaction Patterns
- Oxidation: Alcohols can be oxidized into Aldehydes, Ketones, or Carboxylic Acids by adding more bonds to Oxygen.
- Addition: In Alkenes and Alkynes, the double/triple bond can "open up" to add new atoms (like Hydrogen or Halogens).
- Condensation: An Acid and an Alcohol can join together to form an **Ester** + Water. This is how fats and plastics are often made.
Frequently Asked Questions
What is a functional group?
A functional group is a specific group of atoms within a molecule that is responsible for the characteristic chemical reactions of that molecule. They behave similarly regardless of the size of the carbon chain they are attached to.
How do functional groups affect naming?
Functional groups determine the suffix of the organic compound's name. For example, alcohols end in "-ol" (Ethanol), Ketones end in "-one" (Acetone), and Aldehydes end in "-al" (Propanal).
What is the general formula for an Alcohol?
The general formula for an alcohol is R-OH, where "R" represents any alkyl group (carbon chain) and "-OH" is the hydroxyl group.
What is the difference between an Aldehyde and a Ketone?
Both contain a carbonyl group (C=O). In an Aldehyde (R-CHO), the carbonyl is at the END of the carbon chain. In a Ketone (R-CO-R'), the carbonyl is in the MIDDLE, bonded to two other carbons.
Why do alcohols have higher boiling points than alkanes?
Alcohols can form intermolecular Hydrogen Bonds due to their -OH group. These strong forces require more heat energy to break compared to the weak London Dispersion Forces in alkanes, resulting in higher boiling points.
What is an Ester?
An Ester (R-COO-R') is a functional group derived from an acid (usually carboxylic) and an alcohol. They are responsible for the pleasant fruity smells of many fruits and perfumes.
Are ethers reactive?
Ethers (R-O-R') are generally unreactive and quite stable, which makes them excellent solvents for many organic reactions. However, they can form explosive peroxides if left in air for long periods.
What is the suffix for Carboxylic Acids?
Carboxylic Acids use the suffix "-oic acid". For example, a 2-carbon acid is Ethanoic Acid (Acetic Acid).
What is an Amine?
Amines (R-NH₂) are derivatives of Ammonia. They contain a basic nitrogen atom with a lone pair, making them nucleophilic and basic.
What is the difference between Saturated and Unsaturated hydrocarbons?
Saturated hydrocarbons (Alkanes) have only single bonds between carbons. Unsaturated hydrocarbons contain at least one double (Alkene) or triple (Alkyne) bond.