Isomerism
Use this landing page for Cambridge International AS Level Chemistry Topic 13.4: structural isomerism and stereoisomerism, including geometrical (cis/trans) isomerism in alkenes and chiral centres.
Choose an Isomerism Page
Isomers share a molecular formula but differ in structure. Cambridge divides isomerism into structural isomerism (chain, positional and functional group) and stereoisomerism (geometrical and optical). These pages take each type in turn.
Key idea: Structural isomers differ in how their atoms are connected; stereoisomers have the same connectivity but a different arrangement in space. Geometrical isomerism arises from restricted rotation about a C=C bond.
Geometric Isomerism
Restricted rotation about C=C, cis/trans and E/Z isomers, and identifying geometrical isomerism in alkenes and cyclic compounds (13.4.2, 13.4.3, 13.4.5).
Start revisingStructural Isomerism
Chain, positional and functional group isomerism, and deducing the possible isomers for a molecular formula (13.4.1, 13.4.6).
Start revisingOptical Isomerism
Chiral centres, enantiomers and identifying chiral centres in a given structural formula (13.4.2, 13.4.4, 13.4.5).
Start revisingHow to Use These Pages
Start with geometric isomerism, which builds directly on alkene bonding. Structural and optical isomerism pages will follow.
Exam focus: Describe structural isomerism and its three divisions, describe stereoisomerism and its division into geometrical and optical isomerism, explain the origin of cis/trans isomerism in terms of restricted rotation due to the π bond, and identify chiral centres and geometrical isomerism in a given structure.
Copyright notice: This revision page, including its written explanations, layout and teaching sequence, is produced for Online Learning System by Dr. Mohammed Al-Fatah. It is intended for student revision and may not be copied, redistributed or republished without permission.
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