Functional Groups & Homologous Series (Edexcel International AS Chemistry) : Revision Note

Stewart Hird

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Functional Groups & Homologous Series

Homologous series

  • A homologous series is a group of organic compounds that have the same functional group, but each successive member differs by CH2

An Introduction to AS Level Organic Chemistry Ethanol and Propanol, downloadable AS & A Level Chemistry revision notes

Ethanol and propanol belong to the same homologous series

Homologous Series of Alkanes

  • Things we can say about a homologous series:

    • Each member has the same functional group

    • Each member has the same general formula

    • Each member has similar chemical properties

    • Each successive member differs by  -CH

    • Members have gradually changing physical properties, for example, boiling point, melting point and density

  • As a homologous series is ascended, the size of the molecule increases

  • This has an effect on the physical properties, such as boiling point and density

Functional Groups

  • Functional groups determine the physical and chemical properties of molecules

  • The table below shows a summary of common functional groups found in compounds

  • R is any other atom or group of atoms (except for hydrogen)

Functional Groups Found in Compounds Table

An Introduction to AS Level Organic Chemistry Functional Groups, downloadable AS & A Level Chemistry revision notes

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Stewart Hird

Author: Stewart Hird

Expertise: Chemistry Lead

Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.

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