The document discusses various types of chemical bonds, including ionic, covalent, and coordinate covalent bonds, detailing their formation mechanisms, characteristics, and examples. It also covers relevant concepts like electronegativity, properties of ionic and covalent compounds, and intermolecular forces such as hydrogen bonding and London dispersion forces. The information is presented in a structured format, highlighting key features and differences among the types of bonds and their interactions.

1. Excellence Coaching
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(Mentoring is Better
Chap # 5, LECTURE 8
Chemical Bonding
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2. TOPICS:
•
Chemical bonds.
•
Ionic bonds.
•
Mechanism of ionic bond (NaCl) OR (MgO).
•
Characteristics of ionic compounds.
•
Covalent bond.
•
Types of covalent bond.
Single Covalent bond (ii) Double Covalent bond.(iii) Triple Covalent bond.
•
Characteristic of covalent compounds.
•
Electronegativity values.
•
Ionic character of covalent bond.
•
Co-ordinate covalent bonds or Dative covalent bond.
•
Difference between covalent and co-ordinate covalent bond.
•
Metallic bonding. Bond
•
Inter-molecular forces
•
Hydrogen bonding.
Primary bond secondary bond
Chemcial bond Hydrogen bond.
Metallic bond.
Dipole-dipole interaction.
Vander – eaal forces.
London dispersion forces.
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3. INTRODUCTION:
Atoms of all the elements except noble gases have incomplete outermost orbits or shell
and tends to complete them by chemcial combination with the other atoms.
In 1916, W Kossel described the ionic bond which is formed by the
transfer of electron from one atom to another and also 1916, G.N lewis described about
the formation of covalent bond which is formed by the mutual sharing of electrons
between two atoms.
Both these scientists based their ideas on the fact that atoms greatest stability when
they acquire an inert gas electronic configuration.
•CHEMICAL BOND:
The force of attraction which holds the particle (atoms,ion or molecule) of a compound
is called chemical bond. OR
When two or more than two atoms are combined with each other in order to complete
their octet a link between them is produced which is known as chemical bond.
TYPES OF CHEMICAL BOND:
There are three main types of chemical bond.
•Ionic bond or electrovalent bond.
•Covalent bond.
•Co-ordinate bond or dative covalent bond.
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4. IONIC BOND OR ELECTROVALENT BOND:
The electrostatic force of attraction between cation (positive) and anion (negative) ions
is called ionic bond. OR
A chemcial bond which is formed by the complete shifting of electron between two
atoms is called ionic bond or electrovalent bond.
FORMATION OF IONIC BOND (NaCl)
11Na → Na+
+ e-
K = 2,l=8, m=1 k = 2,l=8
17Cl + e-
→ Cl-
K = 2,l = 8,M = 7 K = 2, L = 8,m=8
Na+
+ Cl-
→ NaCl (sodium chloride)
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5. FORMATION OF IONIC BOND (MgO):
12Mg → Mg+2
+ 2e-
K = 2,l=8, m=2 k = 2,l=8
8O + 2e-
→ O-2
K = 2,L = 6 K = 2, L = 8
(magnesium oxide)
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6. EFFECT OF IONIZATION POTENTIAL ON IONIC BOND:
We know that bond is formed by the transference of electron from one atom to
another,so in the formation of ionic bond an element is required which can lose its
electrons from the outer most shell.it is possible to remove electron from the outermost
shell of metals b/c of their low ionization potential values.
EFFECT OF E.N ON IONIC BOND:Ionic bond is generally formed between metals (low
E.N) and non-metal (high E.N) elements.
CONDITION FORM IONIC BOND:
•Ionic bond fromed usually metal and non-metal.
•Metal has low I.P where as non-metal has high electron affinity.
•Difference of E.N between metal and non-metal is greater than 1.7
CHARACTERISTICS OF IONIC COMPOUND:
1. Ionic compounds are generally hard solids due to the strongest bonding forces.
2. Ionic compounds have high melting and boiling points.
3. They are soluble in water and their aqueous solution contain ions.
4. They are non conductors in the solid state as the ions are not free to move. However
they are good conductors of electricity in the fused (molten) and in an aqueous
solution due to free movement of the ions, so they are electrolytes.
5. They are non-volatile.
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7. COVALENT BOND:
A link which is formed by the mutual sharing of electrons b/w two atoms is called
covalent bond.
H2 – molecule:
H.
+ x
H → H.
------- x
H
Bond strength α
EXPLANATION:
In the formation of covalent bond mutual sharing of electron takes place. This mutual
sharing is possible in non-metals, therefore covalent bond is generally formed between
the atoms of non-metals.
for example: In Cl2 molecule, two atoms of chlorine are combined with each other to
form Cl2 molecule. Each atom of chlorine having seven electrons in its valences shell.
These atoms are united with each other by sharing one of its valence electron as shown.
Cl + Cl → Cl – Cl
In this molecule,one shared pair of electrons forms a single covalent bond b/w two
chlorine the atoms,with the formation of a covalent bond the energy of the system is
also decreased.
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8. Cl + Cl → Cl – Cl H = -242 kj/mol.
This released energy lowered the energy of the molecule and the stability of the
compound is also increased.
TYPES OF COVALENT BOND:
•SINGLE COVALENT BOND:
When a covalent bond is formed by sharing of one electron each atom, that it is called
single covalent bond and denoted by (-) single line between the two bonded atoms
E.g:Cl – Cl, H-H, H – Br etc.
•DOUBLE COVALENT BOND:
In a covalent bond, if two electrons are shared from each of the bonded atom then this
covalent bond is called double covalent bond and denoted by (=) two lines E.g: O = O
•TRIPLE COVALENT BOND:
When a covalent bond is formed by sharing of three electrons from each atom then this
type of covalent bond is called triple covalent bond, and denoted by ( ) three lines
b/w the two bonded atom E.g: N N,
the bond distance of multiple bonds are shorter and the bond energies are higher.
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9. CHARACTERISTICS OF COVALENT COMPOUND:
1. Covalent molecules are held together by a weak force known as inter molecular
force of attraction.
2. Because of weak inter molecular force, covalent compounds are liquid or gases at
room temperature covalent compounds that exist in the solid state are relatively soft
and the surface of the molecule is easily scratched.
3. Covalent compounds have low melting and boiling point.
4. Covalent molecular compounds are generally insoluble in water but soluble in
organic solvent.
5. Non-polar compounds do not conduct electricity in the solid, molten or solution.
However, polar covalent compounds conduct electricity in aqueous solution.
6. They are volatile in nature.
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10. CO-ORDINATE COVALENT BOND OR DATIVE COVALENT BOND:
The covalent bond in which both the electron donate by → (single arrow) and the other
atom participating by empty orbital is known as co-ordinate covalent bond and dative
covalent bond. OR
The Co-ordinate covalent bond b/w two atoms is denoted by an arrow (→). The atom
which donates an electron pair is called as a donor of electron and the other atom
involved in this bond is called acceptor.
EXAMPLE : 1: (FORMATION OF AMMONIUM CHLORIDE (NH4Cl):
In a formation of ammonium chloride the nitrogen atom (N) of ammonia (NH3) acts as a
donor of an electron pair and hydrogen ion (H+
) of hydrogen chloride acts as a acceptor
of electron pair. H
NH3 + H
Clө
→ H – N – H Cl-
H
OR NH4Cl
NH
4 +Clө
→ NH4Cl
NH4 → Covalent Bond
NH4

Clө
=> Ionic bond
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11. EXAMPLE:2 (FORMATION OF HYDRONIUM ION (H3O+
)
Hydroium ion is form by the combination of water molecule and hydrogen ion (H+
), in
which the oxygen atom of water acts as a donor and hydrogen ion acts as an acceptor of
electron pair.
H2O + H
→ [H – O H]+
H
OR H3O+
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12. ELECTRONEGATIVITY:(E.N):
The power of an atom to attract the shared paired of electrons towards it self is known
as electronegativity.
E.N (DATA) IA (ALKALI METAL) II-A (ALKALINE EARTH METAL)
F = 4.0 Li = 1.0 Be = 1.5
O = 3.5 Na = 0.9 Mg = 1.2
Cl,N = 3.0 K = 0.8 Ca = 1.0
Br = 2.8 Rb = 0.8 Sr = 1.0
C,I,S = 2.5 Cs = 0.7 Ba = 0.9
P,H = 2.1
B = 1.9
Si = 1.5 CHARACTERISTICS:
•When the difference of E.N values b/w the two bonded atoms is 1.7 or greater than
1.7, the nature of bond would be ionic.
E.g Na Cl ∆ EN = 2.1
The bond in sodium chloride is ionic bond.
•But when it is less than 1.7,the bond in bonded atoms would be covalent bond.
e.g: H – Cl ∆ EN = 0.9 the bond in hydrogen chloride covalent bond.
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13. POLAR COVALENT BOND:
A Covalent bond between two unlike atoms in which the molecules have oppositely
charged ends or a dipole is called polar covalent bond. OR
These are the bonds which are formed when the difference in the electronegativity it if
of bonded atoms is upto 1.7 or 1.0. EXAMPLE: H S+
– OS-
–HS+
, CO2
NON-POLAR COVALENT BOND:
A covalent bond b/w two similar atoms in which electron pair is equally attracted by
both the atoms is called non-polar covalent bond. OR
Covalent bond which form b/w two element have difference in E.N less than “1” or “O”
EXAMPLE: H – H , N N, H2C = CH2,H3C – CH3, CS2, PH3
IONIC CHARACTER OF COVALENT BOND:
In diatomic molecules like Cl2, O2 , I2, H2 both the atoms are identical so the shared
electrons are equally attracted due to identical electronegativities and hence the
molecules are non-polar. When two dissimilar atoms are linked by a covalent bond the
shared electrons are not attracted equally by the two bonded atoms due to
unsymmetrical distribution of electrons one end of the molecules acquire partial
positive charge and the other end acquire a partial negative charge .This character of a
covalent bond is called ionic character of a covalent bond.
H+s
________Cls-
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14. METALLIC BOND:
Electrostatic force of attraction b/w delocalized electron and cation of metal is known as
metallic bond.In terms of electron gas theory. OR
A substance consisting of positively charged ions fixed in a crystal lattice with negatively
charge. Electron moving freely through the crystal. Therefore free electrons acts as
cohesive force which which hold the atoms together and form a metallic bond.
PROPERTIES OF METALS:
Since electrons in metals are free to move from one atom to the next. They are
generally good conductors of electricity.
When metal is heated,the mobile electrons absorb heat energy and transfer to
neighboring electron, this means that metals are and conductors of heat.
The mobile electrons readily absorb light falling upon them and
move to higher energy levels. When they fall back to their original position. They emits
radiation. The causes the metallic luster.
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15. HYDROGEN BONDING OR PROTIC BRIDGE:
Electrostatic force of attraction b/w electropositive hydrogen and electronegativity
element (f,O,N.......etc) is known as hydrogen bonding or protic bridge.
Hydrogen bond but much stronger than wonder waal’s forces hydrogen
bond is represented by (.........)
There are two type of hydrogen bonding.
1. Inter molecular hydrogen bonding.
2. Intra molecular hydrogen bonding.
1.INTER MOLECULAR HYDROGEN BONDING:
The hydrogen bond formed b/w two difference molecule is known as inter molecular
hydrogen bond (Hf, H2O)
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16. 2.INTRA MOELCULAR HYDROGEN BONDING:
The hydrogen bond in which electropositive hydrogen attract with the E.N element
(O,N,f) of same molecule is known as intra molecular hydrogen bonding.
E.G: ortho nitrophenol.
DISPERSION FORCE OR LONDON FORCE:
Dispersion forces, which result from the motion of electrons around atom.
E.G: consider atoms of noble gases e.g He, Ne, Ar etc.let us examine the attractive forces
on neon as an example. The distribution of ten electrons around the nucleus of neon is
spherically symmetrical.
When two (Ne) atoms come extremely close together. The electron
clouds will repel each other. This polarize each molecule and gives rise to an induced or
temporary dipoles and as a result weak attractive forces called dispersion forces also
called london forces.
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17. DIPOLE-DIPOLE FORCE:
A dipole-dipole force is an attractive intermolecular force resulting from the interaction
of the positive and of one molecules with the negative and of other.
E.G: (HCl – molecule).
As chlorine has greater electronegativity than hydrogen, a partial negative charge on
chlorine atom and a partial positive charge on hydrogen are developed. The (H+
- Cl-
) has
permanent dipole movement.
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