1. Ionic Compounds Formulas and Naming for Multivalent Metals

2. Lewis Diagram: Calcium and Oxygen
Review
Lewis Diagram: Calcium and Oxygen
LiS potassium iodide

3. What does multivalent mean?
Some transition metals are multivalent
This means they have more than one ion form
Look at the periodic table (textbook) and locate some multivalent transition metals
The most common ion is listed first
What is the most common ion for Cu? , Au?

5. What are multivalent ions?
For Example: Copper has 2 ion forms
Can be a 1+ or 2+ ion
Copper I Chloride
Copper II Chloride

6. Writing names for multivalent ions
We need to distinguish between the two or three different ion forms
Use roman numerals from I – VII which corresponds to ion charges
For example:
Nickel can have two ion forms, Ni2+ and Ni3+
These are named nickel (II) and Nickel (III)
Metal Ion charge Roman Numeral
1+ I
2+ II
3+ III
4+ IV
5+ V
6+ VI
7+ VII

7. Writing formulas for compounds containing a multivalent metal
There will only be 1 multivalent metal in a compound
It is the metal so it is first in the name (same as ionic compounds)
The roman numeral will indicate which ion form is in the compound

8. Steps for writing formulas for multivalent compounds
Step 1: Identify each ion and its charge
Step 2: Determine the total charges needed to balance positive and negative
Step 3: Note the ratio of positive ions to negative ions
Step 4: Use subscripts to write the formula, 1’s are not shown in subscript

9. Try the formula for titanium (IV) fluoride
Ti4+ and F1-
ions
Total charge to balance
ratio
formula

10. Lowest Common Multiple-A useful Trick
Manganese (III) Sulfide
Lowest common multiple for 3 and 2 is 6
Mn3+ and S2-
ions
Total charge to balance
ratio
formula

11. Writing formulas for compounds that contain a multivalent metal
Key Points:
The metal is always first
The metal is always the positive ion
The metal could be a multivalent metal
Go to the periodic table and check

12. Compound Naming
To name metals with more than one charge we use the Stock system.
In the Stock system, the charge of the metal is indicated by a Roman numeral written after the name of the metal.
Fe2O3 - iron(III) oxide
FeO - iron(II) oxide
PbO2 - lead(IV) oxide
The Stock system should not be used for metals that have only one possible charge.

13. Steps for Writing formulas for compounds that contain a multivalent metal
Step 1: Identify a multivalent metal
Step 2: identify its different ion forms
Step 3: determine the ratio of ions in the formula
Step 4: what is the charge on the negative ion?
Step 5: Balance the positive and negative charges
Step 6: Write the name using roman numerals in brackets, following the positive ion to indicate which ion was used

14. Example: FeI2

16. Example 2: PbF4