Naming Ionic Compounds and
Formulas
Ionic Compounds
Chemical Name: The chemical name tells you
what ions (charged atoms) are in the
compound
eg. Sodium chloride:
has sodium and chlorine in it
Calcium oxide:
Ionic Compounds
Chemical Name: The chemical name tells you
what ions (charged atoms) are in the
compound
eg. Sodium chloride:
has sodium and chlorine in it
Calcium oxide:
has calcium and oxygen in it
How do we write chemical names?
• Rules for naming compounds
1) Start the name with the positive ion (metal)
How do we write chemical names?
• Rules for naming compounds
1) Start the name with the positive ion (metal)
2) The second ion is the negative ion (non-metal)
How do we write chemical names?
• Rules for naming compounds
1) Start the name with the positive ion (metal)
2) The second ion is the negative ion (non-metal)
3) The name of the metal stays the same
How do we write chemical names?
• Rules for naming compounds
1) Start the name with the positive ion (metal)
2) The second ion is the negative ion (non-metal)
3) The name of the metal stays the same
4) The name of the non-metal had a new ending
(the “ide” ending)
What would be the name of the
following compounds
Chlorine and Magnesium:________________________
Nitrogen and Iron:______________________________
Calcium and Bromide:___________________________
Silver and Fluorine:_____________________________
What would be the name of the
following compounds
Chlorine and Magnesium: Magnesium chloride
Nitrogen and Iron: Iron nitride
Calcium and Bromide: Calcium bromide
Silver and Fluorine: Silver fluoride
Write the names of the following
compounds
1) AlI3 _____________________________________________
2) Na2O ____________________________
3) Mg3P2 _____________________________________________
4) AgI ____________________________
5) K2S ____________________________
6) RbF ____________________________
7) Ag3N ____________________________
8) CaI2 ____________________________________________
Write the names of the following
compounds
1) AlI3
2) Na2O
3) Mg3P2
4) AgI
5) K2S
6) RbF
7) Ag3N
8) CaI2
Aluminum iodide
Sodium oxide
Magnesium phosphide
Silver iodide
Write the names of the following
compounds
1) AlI3
2) Na2O
3) Mg3P2
4) AgI
5) K2S
6) RbF
7) Ag3N
8) CaI2
Aluminum iodide
Sodium oxide
Magnesium phosphide
Silver iodide
Potassium sulphide
Rubidium fluoride
Silver nitride
Calcium iodide
Ionic Compounds
Chemical Formula: The chemical formula tells
you what ions (charged atoms) are in the
compound and the relative number of the
ions.
Ionic Compounds
Chemical Formula: The chemical formula tells
you what ions (charged atoms) are in the
compound and the relative number of the
ions.
eg. NaCl:
Ca2O:
Ionic Compounds
Chemical Formula: The chemical formula tells you
what ions (charged atoms) are in the compound
and the relative number of the ions.
eg. NaCl:
has sodium and chlorine in it and it has 1
sodium ion to 1 chlorine ion
Ca2O:
has calcium and oxygen in it and there is
2 calcium ions for every 1 oxygen ion
Writing Chemical Formulas
• Steps for writing a chemical formula
1) Write down the ions with charges
2) Determine how you are going to balance the
charges
Writing Chemical Formulas
• Steps for writing a chemical formula
1) Write down the ions with charges
2) Determine how you are going to balance the
charges
3) Note the ratio of positive to negative ions
4) Write the subscript into the formula
Examples: Zinc nitride
Step 1: write the ions with the
charge
Step 2: Balance the charge
Step 3: Note the ratio of + and -
Step 4: Write the subscripts in
the formula
Zn2+ N3-
Examples: Zinc nitride
Step 1: write the ions with the
charge
Step 2: Balance the charge
Step 3: Note the ratio of + and -
Step 4: Write the subscripts in
the formula
Zn2+ N3They must equal the same
number with different signs
2+ : 2+, 2+, 2+ = 6+
Balanced 
3- : 3-, 3= 6-
Examples: Zinc nitride
Step 1: write the ions with the
charge
Step 2: Balance the charge
Zn2+ N3They must equal the same
number with different signs
2+ : 2+, 2+, 2+ = 6+
Balanced 
3- : 3-, 3= 6-
Step 3: Note the ratio of + and - 3 Zn2+ ions for every
2 N3- ions
Step 4: Write the subscripts in
the formula
Zn3N2
Example: Aluminum chloride
Step 1: write the ions with the
charge
Step 2: Balance the charge
Step 3: Note the ratio of + and Step 4: Write the subscripts in
the formula
Al3+ Cl1They must equal the same
number with different signs
3+ : 3+
= 3+ Balanced

1- : 1-, 1-, 1- = 3-
Example: Aluminum chloride
Step 1: write the ions with the
charge
Al3+ Cl1-
Step 2: Balance the charge
They must equal the same
number with different signs
3+ : 3+
= 3+ Balanced

1- : 1-, 1-, 1- = 3Step 3: Note the ratio of + and - 1 Al3+ ion for every 3 Cl1- ions
Step 4: Write the subscripts in
the formula
AlCl3
Examples
Step 1: write the ions
with the charge
Step 2: Balance the
charge
Step 3: Note the ratio
of + and Step 4: Write the
subscripts in the
formula