11.3 Isomerism

• Isomers are molecules that have the same molecular formula but differently arranged atoms
• The two type of isomerism are structural isomerism and stereoisomerism
• Structural isomers are defined as having the same molecular formula but different structural formulae
• Structural isomers can have

  1. Positional isomerism
  2. Functional group isomerism
  3. Chain isomerism
• Positional isomerism is when the same functional groups are attached to the main chain at different points
• Type of isomerism: Positional isomerism

  
• Functional group isomerism is when the functional groups are different
• Type of isomerism: Functional group isomerism

  
• Chain isomerism is when there's a different arrangement of the hydrocarbon chain
• Type of isomerism: chain isomerism

  
• The existence of isomers makes identifying an unknown organic compound more difficult - there may be a number of compounds with different structures that all have the same molecular formula - analytical methods can tell you about the structure