Functional Groups
IB
Objectives
• Concepts:
• –Functional group, alkane, alkene, alkyne, alcohol,
carbonyl, aldehyde, ketone, carboxylic acid, ether,
ester, amine, amide, halogenoalkane
• –Primary alcohol, secondary alcohol, tertiary alcohol,
primary amine, secondary amine, tertiary amine,
• Skills:
• –Draw and state names of the compounds containing
up to six carbon atoms with the following functional
groups: aldehyde, ketone, carboxylic acid, alcohol,
amide, amine, ester and halogenoalkane.
Functional Groups
• As has already been indicated, alkanes are
relatively unreactive.
• For an organic molecule to be reactive it needs
something additional.
• A site of reactivity in an organic molecule is called
a functional group.
• C=C double is a functional group.
• Other functional groups contain elements other
than C or H, notably O, N and Cl.
Functional Group
• A functional group could be an atom or a
group of atoms within a molecule that is
responsible for its characteristic
chemical reactions.
alkanes
• Only carbon and
hydrogen
H
• All single bonds
• Their names end
with -ane
H
H
C
C
H
H
Ethane
H
alkenes
• Only carbon and H
hydrogen
• A carbon to carbon
double bond
H
• Their names end
with -ene
H
C
C
H
Ethene
alkynes
• Only carbon and
hydrogen
• A carbon to carbon
triple bond
• Their names end
with -yne
H
C
Ethyne
C
H
alcohols
• Only one oxygen
• Has an O-H group
• Can be classified as H
1º/2º/3º according to
position of O-H
group on carbon
skeleton
• They are named as
alkanol
H
H
C
C
H
H
Ethanol
O
H
H
H
H
C
C
H
H
H
O
H
H
H
H
O
H
C
C
C
H
H
H
H
H
H
O
H
C
C
C
H
H
H
C H3
• Primary alcohol
• Secondary alcohol
• Tertiary alcohol
aldehydes
H
• Only one oxygen
• Has a C=O group
C
• C=O group is at the H
end of the carbon
chain, so is next door
H
to a hydrogen atom
• They are named as
Ethanal
alkanal
O
C
H
ketones
• Only one oxygen
• Has a C=O group
• C=O group is not at
H
the end of carbon
chain, so is next
door to 2 carbons
• They are named as
alkanone
H
O
H
C
C
C
H
H
Propanone
H
esters
• Has 2 oxygens
• One oxygen is
H
part of a C=O
bond, the other is
next door,
sandwiched
between two
carbons.
• They are named
as Alkylalkanoate
H
O
H
C
C
O
C
H
H
Methylethanoate
H
carboxylic acids
• Has 2 oxygens
• Has O-H and C=O
groups on the same
carbon atom
H
• This -COOH group
has to be at the end
of a carbon chain.
• They are named as
alkanoic acid
H
C
O
C
O
H
Ethanoic acid
H
ether
• Has 1 oxygen
• No O-H or C=O
group
H
• The oxygen is
sandwiched
between two
carbon atoms
• Their names end
with -ether
H
H
C
C
H
H
H
O
C
H
Ethylmethylether
H
Amines
• Contain Nitrogen
• Has an –NH2 group
• Can be classified as H
1º/2º/3º according to
the number of
carbon atoms
connected to the N
• They are named as
alkyl amine
H
H
C
C
N
H
H
H
Ethylamine
H
Amide
• Has NH2 and C=O
groups on the same
carbon atom
H
• They are named as
alkanamide
H
C
O
C
N
H
H
Ethanamide
H
Haloalkanes
• Have the general
formula R-X where
H
R is an alkyl group
and X is a halogen
• They are named as
haloalkanes
H
H
C
C
H
H
Chloroethane
Cl
What family does it belong to?
H
H
C
H
C
H
What family does it belong to?
H
H
C
O
C
H
H
What family does it belong to?
H
H
H
O
H
C
C
C
H
H
H
H
What family does it belong to?
H
H
C
H
H
O
C
H
H
What family does it belong to?
H
O
H
H
C
C
O
C
H
H
H
What family does it belong to?
H
H
O
H
C
C
C
H
H
H
What family does it belong to?
H
H
H
C
C
O
C
O
H
H
H
What family does it belong to?
H
H
H
C
C
H
C
H
H
C
O
H
H
H
H