INORGANIC
CHEMISTRY
CHEMICAL BONDING
BY – SAGAR VARJATIA SIR
Covalent bond & Ionic bond
V.S.E.P.R Theory
Hybridisation
Questions
Force of attraction which hold two or more than two species together
is know as bond.
Chemical Bonding
Reason
To attain the state of maximum
stability species have tendency
of bonding
Classification of bonds
Oo this basis of type of species
getting bonded bond can be
classify into following categories.
H — H H2O H2O Na+ Cl–
Bond
Interatomic bond
between two
atom strong bond
200-400 kJ/mol
Intermolecular
force between
molecules weak
bond 2-40 kj/mol
➢ Non-metal + Non-metal-covalent bond
➢ Non-metal + Metal – Ionic bond
➢ Metal + Metal-Metallic bond
H-Bond 1. Ion-dipole
2. Dipole-Dipole
3. Ion-Induced dipole
4. Dipole-Induced dipole
5. London force
❑ Coordination bond is type of covalent
bond
Atoms undergoes sharing of electron.
Sharing of electron leads to the
formation of covalent bond.
Valence bond theory
Formation of covalent bond explained by three theories
Covalent bond
Lewis octet theory Valence bond theory
Molecular orbital theory
As per lewis octet theory
Bonding for stability
Stability by achieving Nobel gas
configuration
Lewis octet theory
Covalent bond
Equal sharing-Covalent bond
Unequal sharing-Coordinate bond
Sharing
Incomplete octet molecules
Lewis-kossel approach
To acquire inert gas
configuration atoms loose or
gain (e–) or share
Octet Rule: Tendency of atoms
to achieve eigtht (e–) in their
outermost shell
Exceptions to
octet rule
Expanded octet molecules
Odd (e–) molecules
Shape of molecules
XeF2; XeF4 etc.
Ionic or
electrovalent bond
NaCl; KCl; MgCl2
Electrovalency: Total no. of
(e–) gain or lose by non-metal
and metal to form ion bond
Electrostatic force of attraction
between metal and non-metal
Non-directional bond
No hybridization
No Isomerism
Only empirical formula
Ionic Bond
Q. High lattice Enthalpy?
(i) NaCl MgCl2 AlCl3
(ii) NaCl MgO
Energy released when two oppositively
charged ions combine to form a crystal
lattice
Conductivity
(Molten/Aquacous)
Hard crystalline; brittle
High M.P and B.P
Solubility
{in polar solvents}
1. Low I.E. of metal
2. High electron hain enthalpy of non-metal
3. High lattice Enthalpy
Conditions
Lewis dot structure:
Represents the total no. of (e–)
present in the outermost shell
Molecule with complete
octet and donor atom should
house at least one lone pair
Acceptor atom molecule it
should be electron-deficient
Coordinate bond
Example:
NH3. BF3; NH4Cl; K4 [Fe (CN)6]
Ek tarfa pyaar
Formal Charge:
F.C  [V – L –
𝟏
𝟐
S]
V = Total no. of valence (e–) for
atom in free state
L = Total non-bonded or lone pair
electrons
S  Total no. of shared (e–)
Resonance:
Delocalization of () electrons
. . . .
:O:
||
C
:O–: :O–:
Mutual sharing of electrons
Formation of bond is done with a
release of energy
Covalent Bond
Polar covalent bond
Non-Polar covalent bond
Covalent Bond:
➢ Physical state: In all
F2; Cl2; Br2; I2
gas liquid solid.
➢ Conductivity: Poor
➢ Solubility: Non Polar
➢ Isomerism
➢ Directional Bonds
➢ Slow Reactions
Covalency:
➢ Total of bonds made by central
atom through sharing
➢ Total no. of half filled atomic
orbitals.
➢ Maximum covalency is
generally shown in exited
state.
➢ PCl5 exists but NCl5 doesnot.
Polarization in ionic bond
Small size of cation
Large size of anion
High charge on anion or cation
FAZAN'S RULE
No Bond is 100% Ionic.
Cation: Polarising power
Anion: Polarizability
{Anion gets distorted}
Pseuto Inert gas electronic configuration
Applications of Fazan's Rule:
Polyatomic ions {CO3
2–; SO4
2–; HCO3
–, NO3
–}
I. Thermal decomposition of Metal carbonates
Li2CO3
𝛥
li2O + CO2; But Na2CO3; K2CO3; and rest can't
Increasing thermal li2CO3 < Na2CO3 < K2CO3 < RbCO3 < Cs2CO3. stability
order
For metal Halides: {Small anions: F–; Cl–; O2–; OH–; S2–; N3– etc.}
We see lattice energy rather than polarization concept
LiF > LiCl > LiBr > LiI
 
1
Polarization Covalent character
Thermal
Intensity of Colour:
AgCl AgBr AgI Ag2S
White Pale yellow Dark yellow Black
Cl– < Br– < I– Large size 𝜶 Polarization 𝜶 Intensity of anion
Solubility of Ionic Compounds: {H.E. > L.E.}  Soluble
Case-I: {When rc  ra} {For small anions like: O2–; S2–; N3–; F–; Cl–; OH– etc.}
➢ Lattice energy is the deciding factor:
 H.E. > L.E.
 Solubility ()
Top (As) ()
(L.E.) (  )
Bottom H.E. ()
Ex. liF < NaF < KF < RbF < CsF
MgO < CaO < SrO < BaO
increasing solubility
NaCl > KCl > RbCl > CsCl > liCl
lattice energy ()  Melting point ()
Case-II: {When rc << ra} {SO4
2–; CO3
2–; PO4
3–; NO3
–; I–; Br– }
Top L.E.()  L.E. > H.E. { Solubility decrease}
H.E. (  )
Bottom
Ex.: BeCO3 > MgCO3 > CaCO3 > SrCO3 > BaCO3
BeSO4 > MgSO4 > CaSO4 > SrSO4 > BaSO4
Decreasing solubility
V.S. E. P. R. Theory:
➢ Valence shell electron pair repulsion.
➢ Covalent molecule → Geometry shape find → Valence shell ke electron
Repulsion ko Minimum Rakhna hoga.
➢ Minimum Repulsion → Side atom maximum distance apart →
Maximum bond angle → Molecule stable → Geometry
L.P. – L.P > L.P. – B.P > B.P. – B.P
Case-I: Molecules with Regular Geometry:
Molecular type Geometry and Bond angle Examples
1. AX2
2. AX3
3. AX4
Molecular type Geometry and Bond angle Examples
4. AX5
5. AX6
6. AX7
Case-II: Irregular Geometry:
Molecular type Expected geometry Actual shape Examples
1. AB2L
2. AB2L2
3. AB3L
Molecular type Expected geometry Actual shape Examples
4. AB4L
5. AB3L2
6. AB2L3
Molecular type Expected geometry Actual shape Examples
7. ABs2
8. AB4L2
9. AB6L
(i) It is kind of (Intermolecular) lewis acid-base interaction.
(ii) Partial pi bond or coordinate pi bond.
(iii) Types: (A) p – p Back bonding
(B) p – d Back bonding
(iv) Conditions: Donor atom Acceptor atoms
2nd period 2nd or 3rd period
lone pair vacant orbital
Back Bonding
1. Valence bond theory
Valence bond theory
Proposed by Heitler and London
as per VBT bonding takes place
for attaining stability.
1
Stability
Potential energy

➢ Bond formation is an
exothermic process.
➢ During this process some
extent of electron cloud merge
into each other, this part is
known as overlapped region
and this process is known as
overlapping.
➢ Only those orbitals of valence shell
can exhibit overlapping which has
➢ Unpaired electron
For example:
H-Cl bond form by overlapping of
1s-3p orbitals
H → 1s1
Cl → 1s2 2s2 2p6 3s2 3p5
➢ Opposite spin
Strength of covalent bond
Strength of covalent bond  extent of
overlapping.
1. Nature of orbitals
(a) No. of shell: Lower the number of
shell higher overlapping.
Bond strength 
/size of orbitals
1-1 > 1-2 > 2-2 > 2-3
➢ Exception:
Cl2 > Br2 > F2 > I2 due to lip-lp
O–O < S–S repulsion
N–N < P–P
1
No. of shell
S-non-directional
P-directional
(B) Type of sub-shell
Valence shell contain subshell s and p
Directional orbital has
higher extent of
overlapping.
Possible combination and strength of overlapping
s-s < s-p < p-p
This factor is applicable when number of shell is same
otherwise shell factor prominent 2s - 2s < 2s - 2p < 2p - 2p
sub-shell factor 1s - 1s > 1s - 2s > 1s - 3s shell factor
(a) Axial overlapping:
Along the internuclear
axis; form sigma () bond,
strong bond.
(b) Co-lateral overlapping:
Side wise overlapping has less
extent of overlapping form
-bond
➢ In case of multiple bond between two atom one bond is sigma
and rest are pi-bonds.
➢ VBT was not able to define geometry of molecule therefore a
new concept came into existence known as hybridization.
Hybridisation
➢ Intermixing of atomic orbitals and formation of new orbital these orbitals
are known as hybrid orbital and this concept is known as hybridisation.
➢ It is hypothetical concept.
➢ Only those orbitals can participate in hybridisation which has slight
difference in energy.
➢ No. of hybrid orbitals: No. of atomic orbitals participate in intermixing.
➢ Hybrid orbitals oriented at maximum possible distance three
dimensionally
➢ On the basis of type of orbitals participating in hybridization, we can
divide hybridization into following categorise.
Dipole Moment
Measurement of Polarity in a molecule
μ = q × d
debye = esu-cm
1D = 10-18 esu.cm
(A) Identification of polar or Non-polar molecule.
Molecule: Symmetrical distribution of electron cloud-
Non-polar. Molecule: Unsymmetrical distribution of
electron cloud- Polar.
Diatomic Molecule:
(a) Homoatomic ΔΕΝ = 0 → μ = 0 → Non-polar
H2, F2, Cl2, N2 etc.
(b) Heteroatomic EN ≠ 0 = 0 → μnet = 0 → polar
HF > HCI > HBr > HI
Polyatomic molecule:
R → Vector sum of bond moment
R →
Important Order:
NH3 > NF3
H2O > H2S
CH3Cl > CH3F > CH3Br > CH3I
CH3CI > CH2CI2 > CHCI3 > CCI4
μ1
2
+ μ2
2
+ 2μ1μ2cosθ
Applications:
Predict shape and polarity of molecule Symmetrical geometry →  = 0 → non-
polar Unsymmetrical geometry → µ ≠ 0 → polar Distinguish between cis & trans
form
Dipole moment in Aromatic Compounds
Maleic acid
  0
fumaric acid
 = 0
μ ∝
1
bond angle
Strength
Intermolecular H-bond > Intramolecular H-bond
➢ Intramolecular H-bonding takes place in ortho
derivatives only
Hydrogen Bonding
Electrostatic force of attraction between hydrogen & highly
electronegative atoms.
It is dipole-dipole type of attraction
Hydrogen should be covalently bonded with highly
electronegative elements. Like : F, O & N.
Strength of H-bond  Electronegativity of electronegative
elements should
Type of Hydrogen Bond
Intermolecular Intramolecular
Between molecule Within molecule
➢ It is not an intermolecular
force
➢H₂O is liquid while H2S is gas.
➢HF is liquid while HCl is gas.
EXAMPLES
Applications of H-bonding
Physical State (densile nature)  H-bond
Melting Point (mp)  H-bond
Boiling Point (bp)  H-bond
Viscosity  H-bond
Surface Tension  H-bond
Volatility . 1/H-bond
Vapour Pressure . 1/H-bond
Molecular Orbital Theory
Given by Hund & Mulliken given
Given To explain:
➢O2: Paramagnetic nature.
➢Existence of species like H2
+, H2
–
As per MOT bond form by combination of atomic orbitals &
interference of electron wave interference of electron wave
leads to formation of molecular orbitals.
atomic orbitals electron
waves - interference
constructive interference destructive interference
Constructive Interference
same phase wave - bonding molecular orbital (BMO)
Destructive Interference
opposite phase wave - anti-bonding molecular orbital (ABMO)
Therefore by the combination of two atomic orbitals
there is formation of two molecular orbitals; BMO &
ABMO.
➢ Energy level BMO < ABMO,
➢ All atomic orbitals of an atom participate in
combination and form molecular orbitals with
atomic orbitals of another atom.
➢ Energy level of molecular orbital 1s *1s 2s *2s
2px = 2py 2pz *2px *2py 2px
Total electron <14
Internuclear axis = z
➢ Bonding electron (N2) → No. of electrons present in BMO.
➢ Anti-bonding electron (N2) → No. of electrons present in ABMO.
➢ Bond order: No. of Bonds present between two atoms.
➢ Paramagnetic nature: If any molecule orbital contain unpaired
electron either bonding molecular orbital or anti-bonding molecular
orbital it would be paramagnetic otherwise diamagnetic.
➢ Isoelectronic species:
Same bond order - same magnetic properties.
Significant of MOT
B. O. =
N2 − N2
2
Stability of molecule  B.O.
Bond strength  B.O.
Bond length 
1
B. O.
Formation of molecular orbitals by linear
combination of atomic orbitals
Formation of bonding () and antibonding (*) molecular orbitals by the linear
combination of atomic orbitals yA and yB centred on two atoms A and B respectively.
Electronic configuration of Molecules with more than 14 e– :
2p 2p
2s 2s
1s 1s
Electronic configuration of Molecules with less than or equal to 14 e– :
2p 2p
2s 2s
1s 1s
M.O.T for O2:
2p 2p
2s 2s
1s 1s
Increasing
Energy
Types of Questions:
1. Bond Order
2. Stability of O2 molecule
3. Electronic Configuration:
4. Magnetic Character
Paramagnetic
Diamagnetic
5. Magnetic Moment:
6. H.O.M.O :
L.U.M.O :
For N2 :
2p 2p
2s 2s
1s 1s
1. Bond Order
2. Stability of O2 molecule
3. Electronic Configuration:
4. Magnetic Character
5. Magnetic Moment
N2 → N2
+ NO → NO+
O2 → O2
2– O2 → O2
+
In which of the following processes, the bond order has increased and paramagnetic
character has changed to diamagnetic?
QUESTION_2019
A
C
B
D
Bonding Parameter
1.Bond length: Internuclear distance
Factor affecting Bond length
(i) Atomic size: bond length  size [No. of shell]
(ii) EN, Bond length 
1
EN
(iii) Bond order: Bond length 
1
B.O
(iv) Hybridisation : Bond length 
1
%age of s−character
dA−B = rA + rB − 0.09 × ΔENÅ
Bond Angle : Angle between two adjacent bond is
known as bond angle.
bonded atom

bond angle
bond angle
central atom
Factors Affecting Bond Angle
(i) Hybridisation:
Bond angle  %age of s-character
(ii)No. of lp/bp:
[when hybridisation is same]
Bond angle 
1
lp
Eg. : CH4 > NH3 > H2O:
(iii) Type of Central atom: Applicable when :
➢ hybridisation same
➢ No. of Ip/bp same.
Bond angle  EN of central atom
Eg. NH3 > PH3 > AsH3 > SbH3
:
:
Chemical Bonding _ Class Notes.pdf for jee

Chemical Bonding _ Class Notes.pdf for jee

  • 1.
  • 2.
    Covalent bond &Ionic bond V.S.E.P.R Theory Hybridisation Questions
  • 3.
    Force of attractionwhich hold two or more than two species together is know as bond. Chemical Bonding Reason To attain the state of maximum stability species have tendency of bonding Classification of bonds Oo this basis of type of species getting bonded bond can be classify into following categories. H — H H2O H2O Na+ Cl– Bond Interatomic bond between two atom strong bond 200-400 kJ/mol Intermolecular force between molecules weak bond 2-40 kj/mol ➢ Non-metal + Non-metal-covalent bond ➢ Non-metal + Metal – Ionic bond ➢ Metal + Metal-Metallic bond H-Bond 1. Ion-dipole 2. Dipole-Dipole 3. Ion-Induced dipole 4. Dipole-Induced dipole 5. London force ❑ Coordination bond is type of covalent bond Atoms undergoes sharing of electron. Sharing of electron leads to the formation of covalent bond. Valence bond theory Formation of covalent bond explained by three theories Covalent bond Lewis octet theory Valence bond theory Molecular orbital theory As per lewis octet theory Bonding for stability Stability by achieving Nobel gas configuration Lewis octet theory Covalent bond Equal sharing-Covalent bond Unequal sharing-Coordinate bond Sharing
  • 4.
    Incomplete octet molecules Lewis-kosselapproach To acquire inert gas configuration atoms loose or gain (e–) or share Octet Rule: Tendency of atoms to achieve eigtht (e–) in their outermost shell Exceptions to octet rule Expanded octet molecules Odd (e–) molecules Shape of molecules XeF2; XeF4 etc.
  • 5.
    Ionic or electrovalent bond NaCl;KCl; MgCl2 Electrovalency: Total no. of (e–) gain or lose by non-metal and metal to form ion bond Electrostatic force of attraction between metal and non-metal Non-directional bond No hybridization No Isomerism Only empirical formula
  • 6.
    Ionic Bond Q. Highlattice Enthalpy? (i) NaCl MgCl2 AlCl3 (ii) NaCl MgO Energy released when two oppositively charged ions combine to form a crystal lattice Conductivity (Molten/Aquacous) Hard crystalline; brittle High M.P and B.P Solubility {in polar solvents} 1. Low I.E. of metal 2. High electron hain enthalpy of non-metal 3. High lattice Enthalpy Conditions
  • 7.
    Lewis dot structure: Representsthe total no. of (e–) present in the outermost shell Molecule with complete octet and donor atom should house at least one lone pair Acceptor atom molecule it should be electron-deficient Coordinate bond Example: NH3. BF3; NH4Cl; K4 [Fe (CN)6] Ek tarfa pyaar
  • 8.
    Formal Charge: F.C [V – L – 𝟏 𝟐 S] V = Total no. of valence (e–) for atom in free state L = Total non-bonded or lone pair electrons S  Total no. of shared (e–) Resonance: Delocalization of () electrons . . . . :O: || C :O–: :O–:
  • 10.
    Mutual sharing ofelectrons Formation of bond is done with a release of energy Covalent Bond Polar covalent bond Non-Polar covalent bond
  • 11.
    Covalent Bond: ➢ Physicalstate: In all F2; Cl2; Br2; I2 gas liquid solid. ➢ Conductivity: Poor ➢ Solubility: Non Polar ➢ Isomerism ➢ Directional Bonds ➢ Slow Reactions Covalency: ➢ Total of bonds made by central atom through sharing ➢ Total no. of half filled atomic orbitals. ➢ Maximum covalency is generally shown in exited state. ➢ PCl5 exists but NCl5 doesnot.
  • 13.
    Polarization in ionicbond Small size of cation Large size of anion High charge on anion or cation FAZAN'S RULE No Bond is 100% Ionic. Cation: Polarising power Anion: Polarizability {Anion gets distorted} Pseuto Inert gas electronic configuration
  • 14.
    Applications of Fazan'sRule: Polyatomic ions {CO3 2–; SO4 2–; HCO3 –, NO3 –} I. Thermal decomposition of Metal carbonates Li2CO3 𝛥 li2O + CO2; But Na2CO3; K2CO3; and rest can't Increasing thermal li2CO3 < Na2CO3 < K2CO3 < RbCO3 < Cs2CO3. stability order For metal Halides: {Small anions: F–; Cl–; O2–; OH–; S2–; N3– etc.} We see lattice energy rather than polarization concept LiF > LiCl > LiBr > LiI   1 Polarization Covalent character Thermal
  • 15.
    Intensity of Colour: AgClAgBr AgI Ag2S White Pale yellow Dark yellow Black Cl– < Br– < I– Large size 𝜶 Polarization 𝜶 Intensity of anion Solubility of Ionic Compounds: {H.E. > L.E.}  Soluble Case-I: {When rc  ra} {For small anions like: O2–; S2–; N3–; F–; Cl–; OH– etc.} ➢ Lattice energy is the deciding factor:  H.E. > L.E.  Solubility () Top (As) () (L.E.) (  ) Bottom H.E. ()
  • 16.
    Ex. liF <NaF < KF < RbF < CsF MgO < CaO < SrO < BaO increasing solubility NaCl > KCl > RbCl > CsCl > liCl lattice energy () Melting point () Case-II: {When rc << ra} {SO4 2–; CO3 2–; PO4 3–; NO3 –; I–; Br– } Top L.E.()  L.E. > H.E. { Solubility decrease} H.E. (  ) Bottom
  • 17.
    Ex.: BeCO3 >MgCO3 > CaCO3 > SrCO3 > BaCO3 BeSO4 > MgSO4 > CaSO4 > SrSO4 > BaSO4 Decreasing solubility
  • 18.
    V.S. E. P.R. Theory: ➢ Valence shell electron pair repulsion. ➢ Covalent molecule → Geometry shape find → Valence shell ke electron Repulsion ko Minimum Rakhna hoga. ➢ Minimum Repulsion → Side atom maximum distance apart → Maximum bond angle → Molecule stable → Geometry L.P. – L.P > L.P. – B.P > B.P. – B.P
  • 19.
    Case-I: Molecules withRegular Geometry: Molecular type Geometry and Bond angle Examples 1. AX2 2. AX3 3. AX4
  • 20.
    Molecular type Geometryand Bond angle Examples 4. AX5 5. AX6 6. AX7
  • 21.
    Case-II: Irregular Geometry: Moleculartype Expected geometry Actual shape Examples 1. AB2L 2. AB2L2 3. AB3L
  • 22.
    Molecular type Expectedgeometry Actual shape Examples 4. AB4L 5. AB3L2 6. AB2L3
  • 23.
    Molecular type Expectedgeometry Actual shape Examples 7. ABs2 8. AB4L2 9. AB6L
  • 24.
    (i) It iskind of (Intermolecular) lewis acid-base interaction. (ii) Partial pi bond or coordinate pi bond. (iii) Types: (A) p – p Back bonding (B) p – d Back bonding (iv) Conditions: Donor atom Acceptor atoms 2nd period 2nd or 3rd period lone pair vacant orbital Back Bonding
  • 26.
    1. Valence bondtheory Valence bond theory Proposed by Heitler and London as per VBT bonding takes place for attaining stability. 1 Stability Potential energy  ➢ Bond formation is an exothermic process. ➢ During this process some extent of electron cloud merge into each other, this part is known as overlapped region and this process is known as overlapping. ➢ Only those orbitals of valence shell can exhibit overlapping which has ➢ Unpaired electron For example: H-Cl bond form by overlapping of 1s-3p orbitals H → 1s1 Cl → 1s2 2s2 2p6 3s2 3p5 ➢ Opposite spin Strength of covalent bond Strength of covalent bond  extent of overlapping. 1. Nature of orbitals (a) No. of shell: Lower the number of shell higher overlapping. Bond strength  /size of orbitals 1-1 > 1-2 > 2-2 > 2-3 ➢ Exception: Cl2 > Br2 > F2 > I2 due to lip-lp O–O < S–S repulsion N–N < P–P 1 No. of shell
  • 27.
    S-non-directional P-directional (B) Type ofsub-shell Valence shell contain subshell s and p Directional orbital has higher extent of overlapping. Possible combination and strength of overlapping s-s < s-p < p-p This factor is applicable when number of shell is same otherwise shell factor prominent 2s - 2s < 2s - 2p < 2p - 2p sub-shell factor 1s - 1s > 1s - 2s > 1s - 3s shell factor (a) Axial overlapping: Along the internuclear axis; form sigma () bond, strong bond. (b) Co-lateral overlapping: Side wise overlapping has less extent of overlapping form -bond ➢ In case of multiple bond between two atom one bond is sigma and rest are pi-bonds. ➢ VBT was not able to define geometry of molecule therefore a new concept came into existence known as hybridization. Hybridisation ➢ Intermixing of atomic orbitals and formation of new orbital these orbitals are known as hybrid orbital and this concept is known as hybridisation. ➢ It is hypothetical concept. ➢ Only those orbitals can participate in hybridisation which has slight difference in energy. ➢ No. of hybrid orbitals: No. of atomic orbitals participate in intermixing. ➢ Hybrid orbitals oriented at maximum possible distance three dimensionally ➢ On the basis of type of orbitals participating in hybridization, we can divide hybridization into following categorise.
  • 29.
    Dipole Moment Measurement ofPolarity in a molecule μ = q × d debye = esu-cm 1D = 10-18 esu.cm (A) Identification of polar or Non-polar molecule. Molecule: Symmetrical distribution of electron cloud- Non-polar. Molecule: Unsymmetrical distribution of electron cloud- Polar. Diatomic Molecule: (a) Homoatomic ΔΕΝ = 0 → μ = 0 → Non-polar H2, F2, Cl2, N2 etc. (b) Heteroatomic EN ≠ 0 = 0 → μnet = 0 → polar HF > HCI > HBr > HI Polyatomic molecule: R → Vector sum of bond moment R → Important Order: NH3 > NF3 H2O > H2S CH3Cl > CH3F > CH3Br > CH3I CH3CI > CH2CI2 > CHCI3 > CCI4 μ1 2 + μ2 2 + 2μ1μ2cosθ Applications: Predict shape and polarity of molecule Symmetrical geometry →  = 0 → non- polar Unsymmetrical geometry → µ ≠ 0 → polar Distinguish between cis & trans form Dipole moment in Aromatic Compounds Maleic acid   0 fumaric acid  = 0 μ ∝ 1 bond angle
  • 30.
    Strength Intermolecular H-bond >Intramolecular H-bond ➢ Intramolecular H-bonding takes place in ortho derivatives only Hydrogen Bonding Electrostatic force of attraction between hydrogen & highly electronegative atoms. It is dipole-dipole type of attraction Hydrogen should be covalently bonded with highly electronegative elements. Like : F, O & N. Strength of H-bond  Electronegativity of electronegative elements should Type of Hydrogen Bond Intermolecular Intramolecular Between molecule Within molecule ➢ It is not an intermolecular force ➢H₂O is liquid while H2S is gas. ➢HF is liquid while HCl is gas. EXAMPLES Applications of H-bonding Physical State (densile nature)  H-bond Melting Point (mp)  H-bond Boiling Point (bp)  H-bond Viscosity  H-bond Surface Tension  H-bond Volatility . 1/H-bond Vapour Pressure . 1/H-bond
  • 31.
    Molecular Orbital Theory Givenby Hund & Mulliken given Given To explain: ➢O2: Paramagnetic nature. ➢Existence of species like H2 +, H2 – As per MOT bond form by combination of atomic orbitals & interference of electron wave interference of electron wave leads to formation of molecular orbitals. atomic orbitals electron waves - interference constructive interference destructive interference Constructive Interference same phase wave - bonding molecular orbital (BMO) Destructive Interference opposite phase wave - anti-bonding molecular orbital (ABMO) Therefore by the combination of two atomic orbitals there is formation of two molecular orbitals; BMO & ABMO. ➢ Energy level BMO < ABMO, ➢ All atomic orbitals of an atom participate in combination and form molecular orbitals with atomic orbitals of another atom. ➢ Energy level of molecular orbital 1s *1s 2s *2s 2px = 2py 2pz *2px *2py 2px Total electron <14 Internuclear axis = z ➢ Bonding electron (N2) → No. of electrons present in BMO. ➢ Anti-bonding electron (N2) → No. of electrons present in ABMO. ➢ Bond order: No. of Bonds present between two atoms. ➢ Paramagnetic nature: If any molecule orbital contain unpaired electron either bonding molecular orbital or anti-bonding molecular orbital it would be paramagnetic otherwise diamagnetic. ➢ Isoelectronic species: Same bond order - same magnetic properties. Significant of MOT B. O. = N2 − N2 2 Stability of molecule  B.O. Bond strength  B.O. Bond length  1 B. O.
  • 32.
    Formation of molecularorbitals by linear combination of atomic orbitals Formation of bonding () and antibonding (*) molecular orbitals by the linear combination of atomic orbitals yA and yB centred on two atoms A and B respectively.
  • 34.
    Electronic configuration ofMolecules with more than 14 e– : 2p 2p 2s 2s 1s 1s
  • 35.
    Electronic configuration ofMolecules with less than or equal to 14 e– : 2p 2p 2s 2s 1s 1s
  • 36.
    M.O.T for O2: 2p2p 2s 2s 1s 1s Increasing Energy
  • 37.
    Types of Questions: 1.Bond Order 2. Stability of O2 molecule 3. Electronic Configuration: 4. Magnetic Character Paramagnetic Diamagnetic
  • 38.
    5. Magnetic Moment: 6.H.O.M.O : L.U.M.O :
  • 39.
    For N2 : 2p2p 2s 2s 1s 1s
  • 40.
    1. Bond Order 2.Stability of O2 molecule 3. Electronic Configuration: 4. Magnetic Character 5. Magnetic Moment
  • 41.
    N2 → N2 +NO → NO+ O2 → O2 2– O2 → O2 + In which of the following processes, the bond order has increased and paramagnetic character has changed to diamagnetic? QUESTION_2019 A C B D
  • 42.
    Bonding Parameter 1.Bond length:Internuclear distance Factor affecting Bond length (i) Atomic size: bond length  size [No. of shell] (ii) EN, Bond length  1 EN (iii) Bond order: Bond length  1 B.O (iv) Hybridisation : Bond length  1 %age of s−character dA−B = rA + rB − 0.09 × ΔENÅ Bond Angle : Angle between two adjacent bond is known as bond angle. bonded atom  bond angle bond angle central atom Factors Affecting Bond Angle (i) Hybridisation: Bond angle  %age of s-character (ii)No. of lp/bp: [when hybridisation is same] Bond angle  1 lp Eg. : CH4 > NH3 > H2O: (iii) Type of Central atom: Applicable when : ➢ hybridisation same ➢ No. of Ip/bp same. Bond angle  EN of central atom Eg. NH3 > PH3 > AsH3 > SbH3 : :