Halogenoalkanes - Introduction (Edexcel IAL Chemistry)

Spec point — 10.7

Halogenoalkanes - Introduction

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

Exam Hint You are also expected to be able to draw structural, displayed and skeletal formulae of halogenoalkanes