Covalent Bonding

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Covalent Bonding
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Illustration of the formation of the Covalent
bond between Hydrogen and Chlorine

• HCl

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Hydrogen(H)
Hydrogen is a gas. Hydrogen has only 1 electron
in its outer shell
11P 12N
Hydrogen H 2,1
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Chlorine (Cl)
Chlorine is a poisonous gas. It has 7 electrons
in the outside shell and is not stable.
18P 17N
Chlorine 2,8,7
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Neither Hydrogen nor Chlorine are stable, since
both have less than 8 electrons in their outside
shell. However this can easily be achieved by
combining H and Cl together.
Watch how!

1P 0 N

17P 18N
H
Cl
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A covalent bond will be formed between H and Cl
by sharing a pair of electrons .
A Hydrogen atom has only 1 electron which it
cannot lose. Therefore , the only type of bond H
can form is a covalent bond


17P 18N
1P 0N
H
Cl
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HCl
1 atom of Hydrogen has combined with 1 atom of
Chlorine. Both H and Cl are now in a stable state
- each with a full outer shell.


17P 18N
1P 0N
H
Cl
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Satisfying the Octet Rule..
The Octet Rule

• The Octet rule is simply a rule which helps us to
  understand bonding

• Atoms bond together so that each atom attains an
  electron arrangement of 8 electrons in its
  outermost shell.

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To satisfy the Octet Rule, atoms tend to gain,
lose or share electrons
H and Cl shared one pair of electrons

• The H began with 1 electron in its outer shell -
  It needed 2.

• The Cl atom began with 7 electrons in its outer
  shell - It needed 8.

By sharing the pair of electrons, both atoms are
now in a stable state. H has 2 electrons in its
outer shell and Cl has 8 in its outer shell.
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H
Other examples of Covalent Bonds
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1 atom of Hydrogen has combined with 1 atom of
Hydrogen. Both Hydrogens are now in a stable
state - each with a full outer shell.

1P 0N
1P 0N
H
H
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The Water molecule
H
O
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1P 0N
H

8P 8N
H
1P 0N
O
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Both Na and Cl now have 8 electrons in their
outside shell and a new compound NaCl has been
formed


11P 12N

17P 18N
Cl- 2,8,8
Na 2,8
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Both Na and Cl now have 8 electrons in their
outside shell and a new compound NaCl has been
formed



11P 12N

17P 18N
Strong forces of attraction exist between Na and
Cl- and hold the bond together
Cl- 2,8,8
Na 2,8
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