Geometric

• Cis-Trans isomerism is a type of E/Z isomerism
• What is E/Z isomerism caused by?

  restricted rotation of pi bonds
• Atoms with a high atomic number have a higher priority
• Describe cis-trans isomerism:

  • each carbon must have a hydrogen group
  • the two substituent groups attached to the carbon atoms are the same
  • cis isomers have the highest priority groups on the same side of the double bond (above or below)
  • trans isomers have the highest priority groups on opposite sides ( above and below)
• Describe E/Z isomerism:

  • The same substituent group cannot be on the same carbon atom
  • Z isomers have the highest priority groups on the same side of the double bond (above or below)
  • E isomers have the highest priority groups on opposite sides (above and below)
• Assign priority by finding the atom with the highest atomic number - has the highest priority