Unit 14
A: Understand the structures, reac ons, and proper es of func onal group
compounds.
1
 ti ti ti
, Func onal groups
A func onal group is a group of atoms or bonds inside a
substance that is responsible for the compound's unique
chemical reac ons. Regardless of the chemical in which it
is found, the same func onal group will behave similarly
by undergoing iden cal reac ons, each func onal group
has its own dis nguishing proper es.
Figure 1
Func onal groups are important in guiding and managing natural reac ons.
Func onal groups can be categorised into three groups:
1) Primary
2) Secondary
3) Ter ary
Halogenoalkanes
Halogenoalkanes are alkanes in which one or more halogen atoms have replaced the
hydrogen atom in their structure. Halogenoalkanes are divided into three types based
on the posi on of the halogen atom on the carbon atom chain.
Primary halogenoalkanes (1°)
In primary halogenoalkanes, only one alkyl group is linked to the carbon containing
the halogen atom. There is only one R group in primary halogenoalkanes.
2
ti ti ti ti titi ti ti ti ti ti ti
, Secondary halogenoalkanes (2°)
In secondary halogenoalkanes, two alkyl groups are directly linked to the carbon
containing the halogen atom. There are two R groups in secondary halogenoalkanes.
Ter ary halogenoalkanes (3°)
In ter ary halogenoalkanes, three alkyl groups are directly linked to the carbon
containing the halogen atom. There are three R groups in ter ary halogenoalkanes.
Halogenoalkanes can be produced from two methods:
1. Reac ons of alkenes with hydrogen halides.
3
ti titi
ti