1. How charged atoms come together to make compounds
5.6 & 5.7 Ionic Compounds
How charged atoms come together to make compounds

2. RECALL Non-metals gain electrons and become negatively charged anions
Metals lose electrons and become positively charged cations
Atoms lose or gain electrons in order to achieve a full valence orbit of electrons

3. Opposites Attract
Elements combine in specific ratios to balance their charges. Must have a net charge = 0
IONIC COMPOUNDS -Compounds that are made of positive and negative ions
IONIC BOND - attraction that holds oppositely charged ions together in a compound

4. Example 1 NaCl Na  metal, loses one electron
Charge is +1
Cl  non-metal, gains one electron
Charge is -1
Na+ and Cl- makes NaCl

5. Example 2
What is the formula for the ionic compound formed by calcium and iodine?
Step 1) Determine the number of valence electrons , and charge on each atom
Iodine is found in column
17, so we know it has
Ca a charge of 1-
Calcium has a charge of 2+ Iodine has a charge of 1- 2 8 8 2

6. Example 2 cont’d
Step 2:
Write the elements side by side with charges on top:
Ca I1-
Step 3: Cross the charges to determine the amount of each atom in the compound:
Step 4: write the final compound
CaI2

7. Example 3
Write the formula for the ionic compound formed between Sodium and Oxygen
Step 1/2: Determine the charges on Na and O and write above:
Na O 2-
Step 3 : Cross the charges
Step 4: Write the final ionic compound
Na2O

8. Example 4
Write the formula for the ionic compound formed between Aluminum and Sulfur
Step 1/2: Determine the charges on Al and S and write above:
Al S 2-
Step 3 : Cross the charges
Step 4: Write the final ionic compound
Al2S3

9. Tricks to Formulas Write symbols (with metal first)
Write ionic charges above the symbol (from periodic table)
Balance the number of each atom needed to reach a total charge of 0 (criss cross)
Write formula with subscripts (small numbers following the atomic symbols)

10. Naming Ionic Compounds
Metal name is the same as it is on the periodic table
Non-metal name has the ending after the stem changed to “ide”
Examples
NaCl 
Na2O 
CaBr2

11. Tricks to naming Metal ALWAYS comes first
It doesn’t matter how many of each atom you have the name does not change
Examples
AlN
Al2S3