Welcome to
Chemical Bonding and Molecular Structure
Quick Recap
1
2
3 5
4
Chemical Bond and its Types
Formal Charge
Valence Bond
Theory
Kossel-Lewis Theory
Octet Rule and its
Limitations
Orbital Overlap Concept
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Chemical BondingClip 10_21JEE11CHE04NH
(0:03:45 to 0:05:42
Ab aap dekhe
sahi honi chahiye
0:01:57
● Covalent bond formation occurs when appropriately oriented atomic orbitals of the combining atoms undergo overlapping
● Each orbital should have one electron with opposite spin
Key Takeaways
Orbital Overlap Concept
Directional Nature of Covalent Bonds
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 11_21JEE11CHE04NHChemical Bonding and Molecular Structure
(0:05:46 to 0:11:06)
Covalent bond jo ban rha h
Thik hai
0:05:20
Key Takeaways
● Positive overlapping
● Negative overlapping
● Zero overlapping
Positive overlapping is allowed while negative and zero overlapping aren’t.
Types of overlaps based on direction:
Covalent Bond
Covalent bond
Sigma (σ) bond Pi (𝛑) bond
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 12_21JEE11CHE04NHChemical Bonding and Molecular Structure
(0:18:57 to 0:22:49)
Along the axis
Dikha diya hai
0:03:52
● End to end or head on overlap of the bonding orbitals along the internuclear axis form sigma bond.
Key Takeaways
↿ ⇂ ↿⇂
↿ ⇂ ↿⇂
↿ ⇂ ↿⇂
s s
s p
pp
s-s overlap
s-p overlap
p-p overlap
Key Takeaways
Axial or Head on Overlapping
Can undergo rotation about the internuclear axis
Sigma Bond
Covalent Bond
Covalent bond
Sigma (σ) bond Pi (𝛑) bond
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 13_21JEE11CHE04NHChemical Bonding and Molecular Structure
(0:22:56 to 0:27:43)
hum pi bond ki
Jiska hume anumaan hona chahiye
0:04:47
Key Takeaways
● The overlap where the axes of the combining orbitals are perpendicular to the internuclear axis forms pi bond.
+ or
Lateral or Sidewise Overlapping
Cannot undergo rotation about the internuclear axis
𝛑 Bond
Pi (𝛑) Bond
Generally, 𝛑 bond between two atoms is formed in addition to a σ bond
Let Us Solve a Question
TEACHER
Fill the boxes on right based on the type of bond formed:
Orbitals Interacting
Approaching along
Bond Formed
px + px
x-axis
y-axis
z-axis
py + py
x-axis
y-axis
z-axis
In general, 𝛔 bond is stronger than 𝜋 bond
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 14_21JEE11CHE04NHChemical Bonding and Molecular Structure
(0:36:33 to 0:38:57)
In general
Ji haan bilkul
0:02:24
● Greater the extent of overlapping between the two atomic orbital, stronger will be the bond.
Key Takeaways
Strength of Different σ bonds
Extent of Overlapping
Less diffused and provide less area for
overlapping
s orbital spherical in
shape
Extent of Overlapping
Provides greater area for
overlapping
Directional in Naturep-Orbital
For same value of n
s - s overlap s - p overlap p - p overlap< <
3s - 3s overlap 2s - 2s overlap 1s - 1s overlap< <
For different value of n
Extent of Overlapping
Strength of different 𝛑 bonds
2p𝜋 - 2p𝜋 overlap 3p𝜋 - 3p𝜋 overlap>>
Order of Strength of Pi Bonds
(2p𝛑 - 2p𝛑 bond)2p 2p
(3p𝛑- 3p𝛑 bond)3p 3p
Order of Strength of Pi Bonds
Limitations of VBT
Paramagnetic nature of O2could not be
explained
Limitations of VBT
Fails to account for the
geometry and shapes of
various molecules
Limitations of VBT
Valence Shell Electron Pair Repulsion Theory (VSEPR)
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 15_21JEE11CHE04NH
Chemical Bonding and Molecular structure
(0:03:44 to 0:08:56)
Kya khti hai VSEPR theory
Other as possible fine
0:04:34
● Shape of a molecule depends upon the number of valence shell electron pairs around the central atom.
● Valence shell is taken as a sphere with the electron pairs localising on the spherical surface.
● Electron pairs in the valence shell repel one another since they are negatively charged.
● Electron pairs occupy positions in space that tend to minimise repulsion.
Key Takeaways
VSEPR Theory
Let UsContinue...
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 16_21JEE11CHE04NH
Chemical Bonding and Molecular structure
(0:09:55 to 0:14:21)
Single bond double
Theek hai
0:04:26
● A multiple bond is treated as a single bonding pair.
● Lone pair occupies more space on the sphere. So, the order of repulsion is: lp - lp > lp - bp > bp - bp
(lp - Lone pair, bp - Bonding pair)
Key Takeaways
VSEPR Theory
Shape of Molecules
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 17_21JEE11CHE04NH
Chemical Bonding and Molecular structure
(0:14:25 to 0:17:24)
Dhyan Rakhna
Rha hoga
0:02:59
Points to remember
● For electronic geometry, both bond pairs and lone pairs are considered.
● For shape, only bond pairs are considered.
● Lone pairs are not a part of the shape but they can alter the shape.
Key Takeaways
General formula: AB2
Geometry and Shape
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 18_21JEE11CHE04NH
Chemical Bonding and Molecular structure(0:18:03 to 0:20:32)
Humare pas A jo h
Issi category me aa jate h
0:02:29
Molecular shape of AB2:
Key Takeaways
Examples: CO2, BeCl2
Bond Angle = 180o
General formula: AB3 and AB2L
Geometry and Shape
VIDEO CAN BE PLACED HERE
Grade:
Chapter:
Timings:
Start:
End:
Duration:
Link:
Clip 19_21JEE11CHE04NH
Chemical Bonding and Molecular structure
(0:20:35 to 0:25:09)
Agar AB3 ho
Angular ya bent
0:04:34
Molecular shape of AB3:
Key Takeaways
Examples: BF3, SO3
Bond Angle = 120o
Molecular shape of AB2L:
Key Takeaways
Examples: SO2, SnCl2
Bond Angle < 120o
General formula: AB4
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
4 4 0 Tetrahedral Tetrahedral
VSEPR
VSEPR
Examples: CH4, NH4, XeO4
Bond Angle = 109.5o
VSEPR
General formula: AB3L
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
4 3 1 Tetrahedral Pyramidal
VSEPR
Examples: NH3, XeO3, PCl3
Bond Angle < 109.5o
VSEPR
General formula: AB2L2
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
4 2 2 Tetrahedral Bent or V shape
VSEPR
Example : H2O
Bond Angle < 109.5o
VSEPR
General formula: AB5
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
5 5 0 Trigonal Bipyramidal
Trigonal Bipyramidal
VSEPR
Example : PCl5
Bond Angle = 90o, 120o, 180o
VSEPR
General formula: AB4L
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
5 4 1 Trigonal Bipyramidal See saw
VSEPR
Example : SF4
Bond Angle < 90o, 120o, 180o
VSEPR
General formula: AB3L2
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
5 3 2 Trigonal Bipyramidal T shape
VSEPR
Example : ClF3
Bond Angle < 90o, 180o
VSEPR
General formula: AB2L3
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
5 2 3 Trigonal Bipyramidal Linear
VSEPR
Example : XeF2
Bond Angle 180o=
VSEPR
General formula: AB6
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
6 6 0 Octahedral Octahedral
VSEPR
Example : SF6
Bond Angle = 90o , 180o
General formula: AB5L
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
6 5 1 Octahedral Square Pyramidal
VSEPR
VSEPR
Example : BrF5
Bond Angle < 90o , 180o
VSEPR
General formula: AB4L2
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
6 4 2 Octahedral Square Planar
VSEPR
Example : XeF4
Bond Angle = 90o, 180o
VSEPR
General formula: AB7
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
7 7 0 Pentagonal bipyramidal
Pentagonal bipyramidal
Example: IF7
Bond Angle 72o, 144o, 90o, 180o
VSEPR
=
VSEPR
General formula: AB6L
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
7 6 1 Pentagonal bipyramidal
Distorted Octahedral
Example: XeF6
VSEPR
VSEPR
General formula: AB5L2
Electron pairs
Bonding pairs
Lone pairs
Electronic Geometry Shape
7 5 2 Pentagonal bipyramidal
Pentagonal Planar
Example: XeF5-
Bond Angle 72o, 144o
VSEPR
=
A Linear and Distorted Octahedral
B See saw and Linear
C T-Shaped and Trigonal Bipyramidal
D Tetrahedral and Linear
The shapes of SF4 and XeF2 respectively are:
The shapes of SF4 and XeF2 respectively are:
A Linear and Distorted Octahedral
B See saw and Linear
C T-Shaped and Trigonal Bipyramidal
D Tetrahedral and Linear
A
B
C
D
XeF2O2
PCl5
AsH4
XeF4
In which of the following species maximum atom can lie in same plane?
A
B
C
D
XeF2O2
PCl5
XeF4
In which of the following species maximum atom can lie in same plane?
AsH4
Molecular shapes of SF4, CF4 and XeF4 are:
A
B
C
D
The same, with 2, 0 and 1 lone pair of electrons respectively
The same, with 1, 1 and 1 lone pair of electrons respectively
Different, with 0, 1 and 2 lone pair of electrons respectively
Different, with 1, 0 and 2 lone pair of electrons respectively
A
B
C
D
The same, with 2, 0 and 1 lone pair of electrons respectively
The same, with 1, 1 and 1 lone pair of electrons respectively
Different, with 0, 1 and 2 lone pair of electrons respectively
Different, with 1, 0 and 2 lone pair of electrons respectively
Molecular shapes of SF4, CF4 and XeF4 are:
THANK YOU