3. MEET THE ATTACKERS
I AM A NUCLEOPHILE
I HAVE A LONE PAIR WHICH I CAN
USE TO FORM A NEW BOND.
I ATTACK ELECTRON DEFICIENT
AREAS (those with a + or d+)
7. MEET THE ATTACKERS
AND I AM A FREE RADICAL
I HAVE AN UNPAIRED ELECTRON
WHICH I WANT TO PAIR UP. I AM
VERY REACTIVE AND DON’T MIND
WHERE I ATTACK… WATCH OUT!
9. WHO IS ATTACKED?
THE BONDING IN A MOLECULE
INFLUENCES WHAT WILL ATTACK IT
A typical covalent bond with one shared
SINGLE pair – nothing to tempt an attacking species
Bond has twice as many electrons – species
MULTIPLE
which like electrons will be attracted
Similar atoms have an equal attraction for
NON-POLAR
the shared pair of the covalent bond
d+ d-
Atoms have different electronegativities and
the shared pair will be attracted more to one
POLAR
end – species known as nucleophiles will be
attracted to the slightly positive end
10. WHAT ATTACKS ALKANES?
ALKANES ARE RELATIVELY UNREACTIVE ORGANIC COMPOUNDS
ALKANES CONTAIN TWO BOND TYPES
C-H and C-C
Both bonds are single – no electron rich areas
Bonds are non-polar - no electron deficient areas
Free radicals are very reactive and do attack
FREE RADICAL SUBSTITUTION
11. WHAT ATTACKS ALKENES?
ALKENES ARE MUCH MORE REACTIVE THAN ALKANES
ALKENES CONTAIN A C=C BOND
There will be twice as many electrons between
the carbon atoms as there are in a single bond
C=C bond is double – an electron rich area
Bonds are non-polar - no electron deficient areas
ELECTROPHILIC ADDITION
12. WHAT ATTACKS HALOGENOALKENES?
HALOGENOALKANES ARE MUCH MORE REACTIVE THAN ALKANES
HALOGENOALKANES CONTAIN A POLAR BOND d+ d-
The halogen is more electronegative than the
carbon attracts the shared electron pair.
CH3CH2-Br
Bond is single – not an electron rich area
Bond is polar – the greater electronegativity of
the halogen creates a dipole making the carbon
atom electron deficient.
NUCLEOPHILIC SUBSTITUTION
