Compound Formation – COVALENT COMPOUNDS
The atoms of many non-metals _____________________ electrons with other non-metal atoms. In
covalent bonding, atoms ________________________ slightly, and one _______________________
electron from each atom will pair together.
The pair of electrons involved in a covalent bond are sometimes called the _________________________.
Covalent Compound –
Representing COVALENT COMPOUNDS using a BOHR MODEL
Example 1:
One Nitrogen atom and three Hydrogen atoms
React to form Nitrogen trihydride – NH3
Example 2:
One Carbon atoms and four Hydrogen atoms
React to form Carbon tetrahydride – CH4
Practice: Draw BOHR MODELS for these COVALENT compounds.
1. one Oxygen atom and two Fluorine atoms
React to form Oxygen difluoride
(OF2)
2. one Carbon atom and four fluorine atoms
React to form Carbon tetrafluoride (CF4)
3. one Phosphorus atom and three Hydrogen atoms
React to form Phosphorus trihydride (PH3)
4. one Oxygen atom and two Chlorine atoms
React to form Oxygen dichloride (OCl2)
Representing COVALENT COMPOUNDS using a LEWIS DIAGRAM
Example 1:
One Nitrogen atom and three Hydrogen atoms
React to form Nitrogen trihydride – NH3
Example 2:
One Carbon atoms and four Hydrogen atoms
React to form Carbon tetrahydride – CH4
Practice: Draw LEWIS DIAGRAMS for these COVALENT compounds.
1. one Oxygen atom and two Fluorine atoms
React to form Oxygen difluoride
(OF2)
2. one Carbon atom and four Chlorine atoms
React to form Carbon tetrachloride (CCl4)
3. one Phosphorus atom and three Hydrogen atoms
React to form Phosphorus trihydride (PH3)
4. one Oxygen atom and two Chlorine atoms
React to form Oxygen dichloride (OCl2)
Diatomic Molecules (Covalent Bonds between two of the same non-metal)
Another way that atoms use covalent bonds is to form Diatomic Molecules = a pair of atoms of the
________ element that are joined by ___________________________ bonds.
By joining together, each atom can achieve a full valence shell and therefore become _________________.
There are eight elements that commonly form diatomic molecules:
_________, _________, __________, __________, __________, __________, __________, and _________.
Example: Fluorine gas (Bohr Model)
Fluorine gas (Lewis Diagram)
Practice: Draw the Bohr Models for the following diatomic molecules.
1. Hydrogen Gas (H2)
2. Chlorine Gas (Cl2)
Draw the Lewis Diagram for the following diatomic molecules.
1. Hydrogen Gas (H2)
2. Chlorine Gas (Cl2)
Covalent Compounds
Covalent compounds contain two __________________.
Example:
CCl4
one molecule of Carbon “C” and four molecules of Chlorine “Cl”
Naming Covalent Compounds:
1. Name the first element (the one furthest one to the left of the periodic table), then
change the ending of the second element to “ide”.
2. Use the Greek prefixes in front of each element to indicate the number of atoms.
GREEK PREFIXES:
1 - Mono
6-
2-
7-
3-
8-
4-
9-
5-
10 -
NOTE: Chemists are lazy. We do not write “mono” in front of the first element (but you still
need it for the second one.
Examples:
P2O5
CO
Writing Chemical Formulae for Covalent Compounds:

Use your knowledge of the Greek prefixes to determine the subscripts.
Examples:
Trinitrogen monoxide
Carbon tetrachloride
Dihydrogen monoxide
Instant Practice: Covalent Compounds
1. Write the names of the following compounds:
a. CO2 __________________________________________
b. N2O __________________________________________
c. PCl3 __________________________________________
d. PBr5 __________________________________________
e. SO2 ___________________________________________
f. N2O4 __________________________________________
g. P4S10 __________________________________________
h. S2F10 __________________________________________
i. NI3 __________________________________________
j. NO __________________________________________
2. Write the formulae for the following compounds:
a. Nitrogen tribromide _________________________
b. Sulphur hexafluoride _________________________
c. Dinitrogen tetrasulphide _________________________
d. Oxygen difluoride _________________________
e. Carbon tetraiodide _________________________
f. Sulphur trioxide _________________________
g. Phosphorus pentachloride _________________________
h. Diiodine hexachloride _________________________
i. Dichlorine monoxide _________________________
j. Xenon hexafluoride _________________________