1. Chemical Names of Ionic Compounds
Lesson 7

2. What are Ionic Compounds?
Ionic compounds are made up of positive and negative ions.
All of the positive and negative ions for a pattern
Negative and positive ions attract.
Negative and negative and positive and positive repel.
Ionic compounds form solid crystals.
Ionic compounds are like a solid stack of bricks.

3. Where does our salt come from?

4. Naming Ionic Compounds
Formula for naming ionic compounds
positive ion + negative ion + -ide.
If a compounds contains 2 elements the first is ALWAYS a metal
If a compounds contains 2 elements the second is ALWAYS a non-metal
For example: magnesium (metal) and oxygen (non-metal).
STEP 1: The positive ion is the first part of the name
STEP 2: The negative ion forms part of the ending of the name
STEP 3: Add -ide to the end of the name
magnesium
oxygen
-ide
Magnesium oxide

5. Try these Calcium and Bromine Calcium bromide Lithium and Nitrogen
P text
Calcium and Bromine
Lithium and Nitrogen
Zinc and Sulfur
Calcium bromide
Lithium nitride
Zinc sulfide

6. Writing formulas for Ionic Compounds
Ionic formulas are based on the ions of the atoms involved
Example: What is the name of Ca3N2?
Ca is the positive ion and is calcium.
N is the negative ion and is nitrogen.
Drop the ending of the negative ion, nitrogen and add -ide.
Calcium nitride

7. Writing formulas for Ionic Compounds continued
Rules for writing formulas of ionic compounds
In an ionic compound, the positive charges balance out the negative charges.
The ratio of positive to negative charges gives the proper formula.
The ratio is always written in reduced form.

8. Example: Hydrogen chloride
Identify each ion and its charge
Determine the total charges needed to balance positive and negative
Note the ratio of positive ions to negative ions
Use subscripts to write the formula, 1’s are not shown in subscript
H+ and Cl-
ions
Total charge to balance
+1 = -1
ratio
1 : 1
formula
HCl

10. Example: Potassium and Sulfur
K+ and S2-
ions
Total charge to balance
+1+1 = -2
ratio
2 : 1
formula
K2S

11. Example: Aluminum and Sulfur
Al3+ and S2-
ions
Total charge to balance
+3+3 =
ratio
2 : 3
formula
Al2S3

12. Formulas are always written in their most reduced form
Ca2+ and O2-
ions
Total charge to balance
+2 = -2
ratio
1 : 1
formula
Ca2O2
Simplify and write in most
reduced form
CaO

13. Homework Key Points from Today Workbook, p62 #1-3
Name of a compound=words
(element names spelled out)
Formula of a compound=symbols
(element symbols and subscripts)
Homework
To help you practice naming ionic compounds and writing ionic formulas
Workbook, p62 #1-3
Text book, p187 #1 a,c,e,g,h,i