Covalent Bonding
Sharing is caring
1
Transfer
Electrons
Unit
Cell
Ionic
Molecule
Metallic
Delocalized
Electrons
(sea of e-)
2
Covalent
Share
Electrons
In covalent bonding,
atoms still want to achieve
a noble gas configuration
(the octet rule).
But rather than
losing or gaining electrons,
atoms share electrons.
3
Covalent Bonds
When one nonmetal
shares one or more
electrons with an
atom of another
nonmetal so both
atoms end up with
eight valence
electrons
4
But rather than losing or gaining
electrons,
atoms now share an electron pair.
The shared electron pair
is called a bonding pair
5
Naming Covalent Compound
6
Covalent bonding
Makes molecules
Specific atoms joined by sharing electrons
Two kinds of molecules:
Molecular compound
Sharing by different elements
Diatomic molecules
Two of the same atom
O2 N2
7
Diatomic elements
There are 7 elements that always form
molecules: H2 , N2 , O2 , F2 , Cl2 , Br2 , I2
The –gens (hydrogen, nitrogen, oxygen and
halogens)
8

NEVER FOUND AS SINGLE ATOMS if “alone”

Their names are just the name of the element

Oxygen by itself means O2
1 and 7
9
Covalent Bond Video
Binary Molecular Compounds
Steps to name compounds
a.
b.
c.
d.

10
Name first element - use entire name
Name second element- change ending to –ide
Prefixes used to indicate number of each atom
Only time that no prefix is used is if the first is a one
Examples:
CCl4 –
As2O3 –
carbon tetrachloride
di arsenic tri oxide
The Prefixes
Mono-monocle
Tetra-Tetris
11
Di-Dialogue Tri- tricycle
Penta- pentagon Octa- octopus
1 mono
2 di The first vowel is often dropped to
avoid the combination of “ao” or “oo”.
3 tri
4 tetra
CO = carbon monoxide (monooxide)
5 penta
P4O10= tetraphosphorus decoxide
6 hexa
7 hepta SO2= sulfur dioxide (doxide)
8 octa
9 nona
10 deca
12
Molecular Nomenclature:
Examples
• CF4
• carbon tetraflouride
• N 2O
• dinitrogen monoxide
• SF6
• sulfur hexafluoride
13
P2O3
• diphosporus trioxide
IF7
• iodine heptafluoride
More Molecular Examples
• arsenic trichloride
• AsCl3
• dinitrogen pentoxide
• N2O5
• tetraphosphorus decoxide
• P4O10
14
Covalent Bonds and Lewis
Structures

Octet Rule: All elements will have 8
electrons around it through a
combination of shared and unshared
electrons.
THERE ARE A FEW EXCEPTIONS!!!
»H
only needs 2 electrons
» Be only needs 4 electrons
»B
only needs 6 electrons
15
Covalent Bonds and Lewis
Structures
Most covalent bonds involve the sharing of:
– 2 electrons (single covalent bond),
– 4 electrons (double covalent bond, or
– 6 electrons (triple covalent bond).
16
Covalent Bonds and Lewis
Structures
We are going to use the N.A.S method:
N = needed
A = available
S = shared
(or halogens)
H
1
O
2
N
3
C
4
# of bonds *
* Element that form the most bonds goes in the middle
17
Covalent Bonds and Lewis
Structures
O 2:
 N = 2 (8)
A= 6+6
 S = 16 – 12

18
= 16
= 12
= 4 (2 bonds)
Covalent Bonds and Lewis
Structures
CO:
N= 8+8
A= 4+6
 S = 16 – 10

19
= 16
= 10
= 6 (3 bonds)
20

Lewis structures (electron dot structures) show the
structure of molecules. (Bonds can be shown with dots
for electrons, or with dashes: 1 dash = 2 electrons)

H2

CCl4

N2
HBr
21

Lewis structures (electron dot structures) show the
structure of molecules. (Bonds can be shown with dots
for electrons, or with dashes: 1 dash = 2 electrons)

H2

CCl4

N2
HBr
22

Lewis structures (electron dot structures) show the
structure of molecules. (Bonds can be shown with dots
for electrons, or with dashes: 1 dash = 2 electrons)

H2

CCl4

N2
HBr
23

Lewis structures (electron dot structures) show the
structure of molecules. (Bonds can be shown with dots
for electrons, or with dashes: 1 dash = 2 electrons)

H2

CCl4

N2
HBr
24

Lewis structures (electron dot structures) show the
structure of molecules. (Bonds can be shown with dots
for electrons, or with dashes: 1 dash = 2 electrons)

H2

CCl4

N2
HBr
25

Lewis structures (electron dot structures) show the
structure of molecules. (Bonds can be shown with dots
for electrons, or with dashes: 1 dash = 2 electrons)

H2

CCl4

N2
HBr
Covalent Bonds and Lewis
Structures
-
NO3 :
 N = 8 + 3 (8)
 A = 5 + 3 (6) + 1
 S = 32 – 24

26
= 32
= 24
= 8 (4 bonds)