Covalent Compounds
The Language of Chemistry
Chemistry has a language all of its own…
Chemistry
English
Element Symbols
Letters
Chemical Formulas
Words
Chemical Equations
Sentences
Each element symbol starts with a capital letter
Covalent Compounds
Covalent bond: atoms share electrons so
each has a full outer shell of 8 electrons
Binary Covalent Compound: compound
made from two non-metals that share
electrons
Non
metal
Non
metal
Covalent compound
Covalent Prefixes
1 = mono2 = di3 = tri4 = tetra5 = penta6 = hexa7 = hepta8 = octa9 = nona10 = deca-
Two notes:
• No “mono” on the first
element name
• If oxygen/oxide: do NOT
include the final “o” or
“a” on the prefix
Covalent Compounds
Formula to Name
Covalent Compounds
Formula to Name
• Formulas will have…
• 2 non-metal elements
• To name:
1. Name of the first element with the prefix
indicating the number of atoms
2. Name of the second element with the prefix
indicating the number of atoms and the suffix
“ide”
Examples
P2O5
SiO
Write the
name for the
following
compounds
Practice
1. CO2
carbon dioxide
2. N2O4
dinitrogen tetroxide
3. P4O10 tetraphosphorus decoxide
4. CO
carbon monoxide
Covalent Compounds
Name to Formula
Covalent Compounds
Name to Formula
• Names will have…
– covalent prefixes before the element name
• To write:
1. Write the symbols of the first and second element
2. Use the covalent prefixes to determine the
subscripts of each element (assume the first
element is “1” if there is no prefix).
Atoms do not form ions when bonding covalently…you
DO NOT need to worry about charges with this type! 
Example
Dinitrogen Tetroxide
Example
Write the
formula for
the following
compounds
Practice
1. carbon monoxide
CO
2. nitrogen dioxide
NO2
3. sulfur tetrachloride
SCl4
A Word of Caution…
“di” and “bi” do not mean the same thing!
di-
bi-
Stands for “2” in covalent
compounds
Means there’s a hydrogen in
the polyatomic anion
Carbon dioxide = CO2
Sodium biphosphate = Na2HPO4
Let’s Practice
Example:
Write the name
for the following
compounds
CO2
Carbon dioxide
N2O4
Dinitrogen tetraoxide
P4O10
Tetraphosphorus decaoxide
CO
Carbon monoxide
Nomenclature Summary
Naming Chemical
Formulas
Starts with a metal or
NH4
2 capital letters = Binary
Ionic
Does not contain a metal
= Binary Covalent
compound
More than 2 elements =
Polyatomic Ionic
Mixed Practice – Ionic and Covalent
Na2O
Example:
Write the name
for the following
compounds
K3PO4
Cu(OH)2
(NH4)2S
MgCl2
Mixed Practice
Example:
Write the name
for the following
compounds
Na2O
Sodium oxide
K3PO4
Potassium phosphate
Cu(OH)2
Copper (II) hydroxide
(NH4)2S
Ammonium sulfide
MgCl2
Magnesium chloride
Nomenclature Summary
Writing Chemical
Formulas
Does not contain
covalent prefixes
Ends with “-ide” (except
hydroxide & cyanide) =
Binary Ionic
Does contain covalent
prefixes = Binary
Covalent compound
All others = Polyatomic
Ionic
Mixed Practice
Example:
Write the
following
chemical
formulas
Magnesium hydroxide
Copper (II) nitrate
Iron (III) oxide
Nitrogen dioxide
Sodium bicarbonate
Mixed Practice
Example:
Write the
following
chemical
formulas
Magnesium hydroxide
Mg(OH)2
Copper (II) nitrate
Cu(NO3)2
Iron (III) oxide
Fe2O3
Nitrogen dioxide
NO2
Sodium bicarbonate
NaHCO3