Optical isomerism

• Define stereoisomers

  Molecules that have the same structural formula but have the atoms arranged differently in space.
• what are the two types of stereoisomers ?

  geometrical (E/Z)

  optical
• when a carbon is bonded to 4 different groups we say that It’s asymmetric carbon

  if a carbon is bonded to fewer than 4 groups or if at least two of the groups are the same We say that its symmetric carbon
• When a molecule contains an asymmetric carbon we say that the molecule is chiral (chiral molecule)
• define chiral carbon

  a carbon atom that has four different atoms or group of atoms attached to it.
• We say that a chiral molecule and its mirror image are…

  Enantiomers of each other

  they are non-Superimposable mirror images of each other.
• what are enantiomers ?

  molecules that are non-superimposable mirror images of each other
• How are EZ isomers different from optical isomers ?

  1. Optical isomers contain a chiral carbon whereas Ez isomers do not
  2. EZ isomers are superimposable, whereas optical isomers are not
• what are the similarities between EZ isomers and optical isomers?

  • both relate to molecules with the same structural formula but different spatial raanagement of atoms
  • they are both types of stereoisomerism
• Enantiomers

  Their physical and chemical properties are identical but they differ in their ability to rotate plane polarised light. Hence these isomers are called optical isomers.
• what is major difference between two enantiomers ?

  one rotates plane polarised light in a clockwise manner

  the other rotates plane polarised light anticlockwise.