Formal charge
A formal charge is the difference between no of valence electrons .
has when
unbonded and the number of electrons it "owns" when bonded .
Formal. = no . of valence -
no of e post bond
Example :
"shared
FC =
=
VE
6
-
-
(NBE
6
-
E(2)
+ BE)
bonds
·
Neutral atoms have a formal charge of Zero
·
lons have a formal charge of the charge of the ion
.
·
Carbocation is a atom
containg positively charged carbon atom
a .
·
Carbanion is an atom
containing a negatively charged carbon atom
.
·
Radical is an atom with an oad no ·
Ofe
VSEPR theory
·
A model to predict 3D structure/molecular shape
.
& valence electrons of central atom far as possible to minimize repuls-
are as away
ions
1880
.
I
:
Linear
Trigonal planar
j
Tetrahedral
,When determing electron-group arrangement :
1 . Of t
Count no
groups including lone pairs
.
2 This doesn't determine shape , merely the subgroup
.
2 molecular shapes of trigonal planar
I
· OR X
/ I
Bent Trigonal planar
A double bond has greaterI density and repels the single bond and so theres
deviation.
3 molecular shapes of tetrahedral
eg Ammonia (NH4)
I & ⑧
E
(107 , 3 %
X X slight deviation
L &
11
Tetrahedral Trigonal planar
8
·
⑧
X / < 1095
S
&
1
Bent (V-shaped)
, Hybridization
·
is
HS #
s
Double bond-pibond and one
sigma bond
sp2
Sp C
*
single bond > Sigma
-
bond o
S
H #S
·
How are double bonds formed ?
3 groups
: 3 orbitals are
required
PPP
s
sp" and one unhybridized p orbital .
·
How is a triple bonded ethyne formed ?
H 2 CH
pp p
S
sp orbital with 2 unhybridized porbitals .
(2 sideways overlap
& formed from S-sp (head on overlap
A formal charge is the difference between no of valence electrons .
has when
unbonded and the number of electrons it "owns" when bonded .
Formal. = no . of valence -
no of e post bond
Example :
"shared
FC =
=
VE
6
-
-
(NBE
6
-
E(2)
+ BE)
bonds
·
Neutral atoms have a formal charge of Zero
·
lons have a formal charge of the charge of the ion
.
·
Carbocation is a atom
containg positively charged carbon atom
a .
·
Carbanion is an atom
containing a negatively charged carbon atom
.
·
Radical is an atom with an oad no ·
Ofe
VSEPR theory
·
A model to predict 3D structure/molecular shape
.
& valence electrons of central atom far as possible to minimize repuls-
are as away
ions
1880
.
I
:
Linear
Trigonal planar
j
Tetrahedral
,When determing electron-group arrangement :
1 . Of t
Count no
groups including lone pairs
.
2 This doesn't determine shape , merely the subgroup
.
2 molecular shapes of trigonal planar
I
· OR X
/ I
Bent Trigonal planar
A double bond has greaterI density and repels the single bond and so theres
deviation.
3 molecular shapes of tetrahedral
eg Ammonia (NH4)
I & ⑧
E
(107 , 3 %
X X slight deviation
L &
11
Tetrahedral Trigonal planar
8
·
⑧
X / < 1095
S
&
1
Bent (V-shaped)
, Hybridization
·
is
HS #
s
Double bond-pibond and one
sigma bond
sp2
Sp C
*
single bond > Sigma
-
bond o
S
H #S
·
How are double bonds formed ?
3 groups
: 3 orbitals are
required
PPP
s
sp" and one unhybridized p orbital .
·
How is a triple bonded ethyne formed ?
H 2 CH
pp p
S
sp orbital with 2 unhybridized porbitals .
(2 sideways overlap
& formed from S-sp (head on overlap
