VSEPR
Intro
Postulat
e
Geometr
y
Example
s
Recap
End
VSEPR
VSEPR
Valance Shell Electron Pair
Repulsion Theory
S
Intro
Postulat
e
Geometr
y
Example
s
Recap
End
VSEPR
Valance Shell Electron Pair
Repulsion Theory
Submitted By Dibyendu Mohanta
Roll No: 158-SEM-2054-020
Intro
Postulat
e
Geometr
y
Example
s
Recap
End
VSEPR
Valance Shell Electron Pair
Repulsion Theory
Submitted By Dibyendu Mohanta
Roll No: 158-SEM-2054-020
Intro
Postulat
e
Geometr
y
Example
s
Recap
End
Intro
Postulat
e
Geometr
y
Example
s
Recap
End
C
H
H
H
H O H
H
Intro
Postulat
e
Geometr
y
Example
s
Recap
End
CH4
H2O
about
Postulat
e
Geometr
y
Example
s
Recap
End
OPTION
01
The Shape of a
molecule
depends upon
the no. of
valance shell
electrons
around the
central atom.
Valance shell ep
tends to occupy
such positions in
space that
minimizes
repulsion
between them.
OPTION
02
OPTION
03
Geometry is
same but
structure will be
different due to
lone pair &
bond pair.
A multiple bond
is treated as a
single electron
pair
OPTION
04
VSEPR Postulates :
about
Postulat
e
Geometr
y
Example
s
Recap
End
VSEPR Postulates :
about
O
H H
O C O
O H
H
6 Valance Electrons
4 Valance Electrons
O
C
O
0 Lone Pairs
2 Bond Pairs
2 Lone Pairs
2 Bond Pairs
OPTION
01
The Shape of a
molecule
depends upon
the no. of
valance shell
electrons
around the
central atom.
about
O C O
116.3 pm
Valance shell ep
tends to occupy
such positions in
space that
minimizes
repulsion
between them.
OPTION
02
about
The Repulsive Interaction Of Electron Pairs
Decreases In The Order :
lp-lp > lp-bp > bp-bp
O
H H
Lone Pairs
More Space To Move Around
Bond Pairs
Less Space To Move Around
OPTION
03
Geometry is
same but
structure will be
different due to
lone pair &
bond pair.
about
All Bonds Are Treated As Single Bonds
1 Single Bond = 1 Electron Pair
1 Double Bond = 1 Electron Super Pair
1 Triple Bond = 1 Electron Super Pair
O
C
O
2 Bond Pair
C
N H
C
N
2 Bond Pair
A multiple bond
is treated as a
single electron
pair
OPTION
04
about
Postulat
e
Geometr
y
Example
s
Recap
End
Determine the Molecular
Geometry, looking at
other atomic nuclei
STEP FIVE
Draw the Lewis Dot
Structure of the
Molecule
STEP TWO
Count The Lone pairs
& Bond Pairs around
Central Atom
STEP THREE
Identify The Central
Atom
STEP ONE
Steps to identify geometry of a molecule
STEP FOUR
Name the Electron –
Group Geometry
about
Postulat
e
Geometr
y
Example
s
Recap
End
Be Cl
Cl
Be Cl
about
Postulat
e
Geometr
y
Example
s
Recap
End
Be Cl
Cl
Be Cl
Cl
about
Postulat
e
Geometr
y
Example
s
Recap
End
Be Cl
Cl
Be Cl
Cl
about
Postulat
e
Geometr
y
Example
s
Recap
End
Be Cl
Cl
180°
Be
Cl Cl
LINEAR Geometry
Other Examples:
O
C
O H
C
N
about
Postulat
e
Geometr
y
Example
s
Recap
End
B
F
120°
120°
120°
F
120°
Lets look at a Structure when there is 3 Bond
Pairs Around a Central Atom
about
Postulat
e
Geometr
y
Example
s
Recap
End
B
F
120°
120° 120°
Trigonal
Planer
Geometry
Other Examples : HCHO
Lets look at a Structure when there is
3 Bond Pairs Around a Central Atom
about
Postulat
e
Geometr
y
Example
s
Recap
End
Lets look at a Structure when there is 2 Bond Pairs &
1 Pairs Around a Central Atom
S
O O
about
Postulat
e
Geometr
y
Example
s
Recap
End
Lets look at a Structure when there is 2 Bond Pairs &
1 Pairs Around a Central Atom
Trigonal Planer
Geometry
Although Same Geometry like BF3 But The Shape Of the
Molecule is - Bent Shape
S
O O
about
Postulat
e
Geometr
y
Example
s
Recap
End
Lets look at a Structure when there is 4 Bond Pairs
Around a Central Atom
C
H
H
H
H
Methane (CH4)
about
Postulat
e
Geometr
y
Example
s
Recap
End
Lets look at a Structure when there is 4 Bond Pairs
Around a Central Atom
Tetrahedral
Methane (CH4)
about
Postulat
e
Geometr
y
Example
s
Recap
End Similar to the Tetrahedral Geometry of CH4 ,
Ammonia (NH3) & Water (H2O) have same Geometry
but different Bent like shape
Tetrahedral
Geometry
Water (H2O)
Ammonia (NH3)
about
Postulat
e
Geometr
y
Example
s
Recap
End
Tetrahedral
Geometry
Water (H2O)
Ammonia (NH3)
Bent -
about
Postulat
e
Geometr
y
Example
s
Recap
End
Postulates Of
VSEPR Theory
Learned About Lone Pair
& Bond Pair Electrons
Steps to find
Geometry of a
Molecule
Geometry Of
Linear Molecules
Geometry Of
Trigonal Planer
Molecules
Geometry Of
Tetrahedral
Molecules
about
Postulat
e
Geometr
y
Example
s
Recap
End
So, Where do we go
from here ?
We have to practice VSEPR problems.
Try to identify Common Mistakes.
Then we will learn about Trigonal Bi-
pyramidal & Octahedral Family.
about
Postulat
e
Geometr
y
Example
s
Recap
End
THANK
YOU

VSEPR Theory