Introduction to Organic Chemistry - Introduction to Functional Groups (A-Level Chemistry)

Introduction to Functional Groups

Functional Groups in Organic Chemistry

Key Terms

Functional groups are atoms or groups of atoms in a compound that determine its characteristic reactions.

A homologous series is a family of organic molecules with the same functional group, similar chemical properties and different numbers of carbon atoms. The length of the carbon chain affects the physical properties of the molecules, which have distinct trends, as the number of carbon atoms increase.


A hydrocarbon is a compound consisting only of carbon and hydrogen atoms.

Organic compounds will have a carbon skeleton like hydrocarbons but will have one or more functional groups added to them.

Carbon-carbon bonds allow for an incredible structural diversity so that hydrocarbons and the carbon skeleton of organic compounds can take the shape of straight chains, branched chains, or ring structures.

Depending on the shape of their carbon skeleton, organic compounds can either be:

  • Aromatic – contain a benzene ring.
  • Aliphatic – contain carbon and hydrogen atoms joined together in straight chains, branched chains or non aromatic rings.
  • Alicyclic – aliphatic compounds in which carbon atoms are arranged in non-aromatic rings with or without side chains.
Introduction to Functional Groups
Introduction to Functional Groups

Depending on the type of carbon-carbon bonds present, organic compounds can either be:

  • Saturated – Only single carbon-carbon bonds are present.
  • Unsaturated – Multiple carbon-carbon bonds are present (including C=C or aromatic rings)

Homologous Series

Hydrocarbon structures can have one or more functional groups added to them, which will determine the reactivity of the compound.

Here you can find a compilation of the main homologous series we will be looking at in the next couple chapters on organic chemistry and their corresponding functional group.

The letter R represents an alkyl group (general formula CnH2n+1) or hydrogen atoms. The letter X represents a halogen atom.

Introduction to Functional Groups
Introduction to Functional Groups
→What is Organic Chemistry?

Organic Chemistry is a branch of Chemistry that deals with the study of carbon compounds, including their properties, structure, and reactions. It encompasses a wide range of chemicals, from those found in living organisms to synthetic materials created in the lab.

→What are Functional Groups in Organic Chemistry?

Functional groups are specific groups of atoms that are present within organic molecules and are responsible for the characteristic properties and reactivity of those molecules. Examples of functional groups include alcohols, amines, and carboxylic acids.

→Why are Functional Groups Important in Organic Chemistry?

Functional groups play a critical role in determining the reactivity of an organic molecule and thus, are key to understanding the behavior of organic compounds. By knowing the functional groups present in a molecule, it is possible to predict its reactivity and properties, including its solubility, boiling point, and ability to participate in chemical reactions.

→What are some Common Functional Groups in Organic Chemistry?

Some common functional groups in organic chemistry include alcohols (OH), amines (NH2), carboxylic acids (COOH), aldehydes (CHO), ketones (CO), and esters (COOR).

→How do Functional Groups Affect the Reactivity of Organic Compounds?

Functional groups affect the reactivity of organic compounds by determining the chemical reactions that they can participate in. For example, alcohols are capable of forming hydrogen bonds, while carboxylic acids can undergo acid-base reactions. The presence of a particular functional group in a molecule can also affect its solubility, boiling point, and other physical properties.

→How do you Identify Functional Groups in Organic Compounds?

Functional groups can be identified through various techniques, bonds, participate in acid-base reactions, or have specific solubility characteristics.

→How do Functional Groups Impact the Synthesis of Organic Compounds?

Functional groups play a crucial role in the synthesis of organic compounds. In organic synthesis, the reactivity of functional groups is used to guide the formation of desired products. For example, the reaction of an alcohol with a carboxylic acid can result in the formation of an ester, a common functional group in fragrances and flavors.

→What is the Importance of Understanding Functional Groups in A-Level Chemistry?

Understanding functional groups is important in A-Level Chemistry as it helps students to understand the reactivity and properties of organic compounds. This knowledge is crucial for understanding reactions in organic chemistry and for the synthesis of new compounds. Additionally, understanding functional groups is essential for advanced studies in areas such as medicinal chemistry and biochemistry.

→How do you Memorize the Characteristics of Different Functional Groups?

To memorize the characteristics of different functional groups, it is helpful to understand the chemical structure and reactivity of each group. Practice is also important, and students can use flashcards or quiz themselves on functional group properties. Additionally, connecting functional groups to real-life applications and examples can help to solidify their understanding and recall.

Still got a question? Leave a comment

Leave a comment

Post as “Anonymous”