Classifying Halogenoalkanes (Edexcel AS Chemistry)

Naming halogenoalkanes

• We use the prefixes 
  • Fluoro for fluorine
  • Chloro for chlroine
  • Bromo for bromine
  • Iodo for iodine
• The name of the halogenoalkane is based on the orignal alkane
  • So CH₃CH₂CH₂Br would be 1-bromopropane 
• The position of the halogen atom must be taken into account 
  • So CH₃CH(Br)CH₃ would be 2-bromopropane 
• Finally the substituents are listed alphabetically
  • So  CH₃CH(Cl)CH₂Br would be 1-bromo-2-chloropropane 

Classifying halogenoalkanes

• Halogenoalkanes can be classified as primary, secondary or tertiary depending on the number of carbon atoms attached to the C-X functional group 
  • A primary halogenoalkane is when a halogen is attached to a carbon that itself is attached to one other alkyl group
  • A secondary halogenoalkane is when a halogen is attached to a carbon that itself is attached to two other alkyl groups
  • A tertiary halogenoalkane is when a halogen is attached to a carbon that itself is attached to three other alkyl groups

Primary, secondary and tertiary halogenoalkanes