Covalent Bonding

1
Covalent Bonding
2
Illustration of the formation of the Covalent
bond between Hydrogen and Chlorine

• HCl

3
Hydrogen(H)
Hydrogen is a gas. Hydrogen has only 1 electron
in its outer shell
1P 0N
Hydrogen H 1,1
4
Chlorine (Cl)
Chlorine is a poisonous gas. It has 7 electrons
in the outside shell and is not stable.
18N 17P
Chlorine 2,8,7
5
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
6
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
7
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
8
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.

9
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.
10
H
Other examples of Covalent Bonds
2
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
11
The Water molecule
H
O
2
1P 0N
H

8P 8N
H
1P 0N
O
12
B. Lewis Structures

• Electron Dot Diagrams
• show valence e- as dots
• distribute dots like arrows in an orbital
  diagram
• 4 sides 1 s-orbital, 3 p-orbitals
• EX oxygen

O
13
B. Lewis Structures

• Octet Rule
• Most atoms form bonds in order to obtain 8
  valence e-
• Full energy level stability Noble Gases

14
B. Lewis Structures

• Nonpolar Covalent - no charges
• Polar Covalent - partial charges

15
C. Molecular Nomenclature

• The Seven Diatomic Elements
• Br2 I2 N2 Cl2 H2 O2 F2

H
N
O
F
Cl
Br
I