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Covalent Bonds Covalent Bond Covalent Bond Covalent Bond Covalent Bond Covalent Bond Covalent Bond Covalent Bond Covalent Bond Covalent Bond

Covalent bonds - Chemistry

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Page 1: Covalent bonds - Chemistry

Covalent Bonds

Covalent Bond

Covalent Bond

Covalent Bond

Covalent Bond

Covalent BondCovalent Bond

Covalent BondCovalent Bond

Covalent Bond

Page 2: Covalent bonds - Chemistry

• Bond that is usually formed between by• Non-metal such as hydrogen , carbon and oxygen

do not lose electron from their outer shell .• They do not form positive ions by losing electrons .

However their outer shells are incomplete. • Electron need to be added to the outer shells to

attain the stability of the noble gas atoms.• When the atoms of two non-metals react , all the

atom need to gain electrons to complete the octet shell of electrons. They can do this by sharing electrons between them .

sharing of electronnon-metal atoms

Page 3: Covalent bonds - Chemistry

Lewis Structure

• Shows how the valence electrons of the atoms are arranged in the molecules .

• Example

a ) A helium atom has two valence electron *click to see

He ..

b ) A neon atom has eight valence electrons

Ne ::. .

. .

Page 4: Covalent bonds - Chemistry

• Rules for Writing Lewis Structuresi ) Add up the valence electrons of all the atom in the molecule. Example : CO2

: C : O O = 16 valence electrons

ii ) Use a pair of electrons to form a bond between each pair of atomsiii ) Arrange it like this

x x o o

x x

o o

x x o o

O : C : O

xxxx

xx

oo oo

oo

Page 5: Covalent bonds - Chemistry

Another example : Hydrogen

H HXO

HH O x

Page 6: Covalent bonds - Chemistry

OxygenO2

ChlorineCl2

IodineI2

NitrogenN2

Phosphorus

P4

SulphurS8

Other molecules the are held together by covalent bond

Page 7: Covalent bonds - Chemistry

Single Bond

Page 8: Covalent bonds - Chemistry

Chlorine Molecule

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ClCl

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Cl Cl

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Cl Cl

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Cl Cl

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Cl Cloctet

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Cl Cloctet

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Cl ClThe octet is achieved byeach atom sharing theelectron pair in the middle

Page 16: Covalent bonds - Chemistry

Cl ClThe octet is achieved byeach atom sharing theelectron pair in the middle

Page 17: Covalent bonds - Chemistry

Cl ClThis is the bonding pair

Page 18: Covalent bonds - Chemistry

Cl ClIt is a single bonding pair

Page 19: Covalent bonds - Chemistry

Cl ClIt is called a SINGLE BOND

Page 20: Covalent bonds - Chemistry

Double bond can also be shown as single dash

Cl - Cl

Page 21: Covalent bonds - Chemistry

Water• H2O

Methane• CH4

Tetrachloromethane• CCL4

Ammonia• NH3

Another example of Single Bond

Page 22: Covalent bonds - Chemistry

Double Bond

sometimes simple is better -_-

Page 23: Covalent bonds - Chemistry

Oxygen

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How will two oxygen atoms bond?

OO

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OOEach atom has two unpaired electrons

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OO

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OO

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OO

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OO

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OO

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OO

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Oxygen atoms are highly electronegative.

So both atoms want to gain two electrons.

OO

Page 33: Covalent bonds - Chemistry

Oxygen atoms are highly electronegative.

So both atoms want to gain two electrons.

OO

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OO

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OO

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OO

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OO

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OOBoth electron pairs are shared.

Page 39: Covalent bonds - Chemistry

6 valence electronsplus 2 shared electrons

= full octet

OO

Page 40: Covalent bonds - Chemistry

6 valence electronsplus 2 shared electrons

= full octet

OO

Page 41: Covalent bonds - Chemistry

two bonding pairs,

OOmaking a double bond

Page 42: Covalent bonds - Chemistry

Double bond can also be shown as double dashes

O = O

Page 43: Covalent bonds - Chemistry

Carbon Dioxide•CO2