Naming Ionic Compounds

Question 1

How do you use the strategy “balancing the charges” for ionic compounds?

Answer 1

Step 1: Write the names of the ionic compounds.
Step 2: Use the periodic table to find the charges and write them down.
Step 3: If you have a “+” and “-“ charge, you need to balance them by writing the chemical formula.

Example:
1) Lithium Oxide (Oxide = Oxygen).
2) Lithium has 1+ (or +) and Oxide has (2-).
2) To balance, you can add another charge to Lithium.
(Li +, Li +, and O 2-)
3) Write the formula: Li2O (no subscript after the “O” means there’s only 1 Oxygen atom).

Question 2

How do you use the strategy “crossover rule” for ionic compounds?

Answer 2

Step 1: Write each element or polyatomic in ionic form.

Step 2: Crossover the charges to make to make them subscripts.

Step 3: Tidy it up and put it together.

Example: Use the crossover rule to write the chemical formula for aluminum chloride.
Step 1: Al 3+ CI 1-
Step 2: AI        CI 
                 1         3
Step 3: AI CI
                     3

Question 3

How do you use the strategy “crossover rule” for polyatomic compounds?

Answer 3

Sodium carbonate
Step 1: Na + CO2-
                            3
Step 2: Na 2  CO
                            3  1
= Na2(CO3)1 
1 - the quantity of polyatomic packages in the structure.

Step 3: Na2CO3

Question 4

How do you name ionic compounds with Multivalent ions?

Answer 4

Transition metals/Roman numerals = multivalent ions

Step 1: Find the charge of the multivalent ion by figuring out the charge of the other ion.
Positive must balance out with negative

Step 2: Write the name of the ionic compound using the chemical formula.

Example: FeCI3
Step 1: Is Fe 2+ or Fe 3+?
- CI = CI 1-
          CI 1-
          CI 1-
- CI 3 - = Fe 3+
 Step 2: Fe 3+ = Iron (III)
CI = Chloride
Name: Iron (III) Chloride

Question 5

What are the 2 exemptions when naming multivalent ionic compounds?

Answer 5

1. Silver (Ag) = Always makes Ag 1+
2. Zinc (Zn) = Always makes
   Zn 2+

DO NOT USE ROMAN NUMERALS