1. Naming Compounds Having Polyatomic Ions
Objective: To learn the names of common polyatomic ions and how to use them in naming compounds.

2. Define polyatomic ion A group of atoms with a charge Some Examples
SO42- CN C2H3O2-
sulfate cyanide acetate
OH- NO NO2-
Hydroxide nitrate nitrite

3. Polyatomic vs. Monatomic
How are the ions S2- and SO42- different?
SO42- is five atoms combined to make one ion.
SO43- is a polyatomic ion

4. Turn to page 100
Note the table listing the most common polyatomic ions.
This table will be supplied to you when you take the test.
Let’s look at it.

5. What do you notice about the names of most polyatomic ions?
Most end with either –ite or –ate.
Notice there are some that end in -ide.

6. Perchlorate ClO4-
chlorate ClO3-
chlorite ClO2-
hypochlorite ClO-
Chloride Cl-

7. Naming Compounds that Contain Polyatomic Ions
Say the name of the positive ion
Say the name of the negative ion
Na2SO K2SO4
sodium sulfite potassium sulfate
KC2H3O2
Potassium acetate

8. This will be easier if you remember this:
Compounds only have two names
CuCO3
Copper(II) carbonate

9. Compounds Containing SO42-
The name of the polyatomic ion is sulfate
BaSO4 Al2(SO4)3
barium sulfate aluminum sulfate
CaSO Na2SO4
calcium sulfate sodium sulfate

10. Compounds Containing OH-
The name of the polyatomic ion is hydroxide
NaOH Cu(OH)2
sodium hydroxide copper(II) hydroxide
Al(OH)3 Fe(OH)2
aluminum hydroxide Iron(II) hydroxide

11. Compounds Containing C2H3O2-
Ba(C2H3O2)2 Cu(C2H3O2)2
Barium acetate copper(II) acetate
Mg (C2H3O2)2 Hg2(C2H3O2)2
Magnesium acetate mercury(I) acetate

12. Compounds Containing H2PO4- The name of the polyatomic ion is dihydrogen phosphate.
NaH2PO4
Remember: Say the name of the positive ion and then the name of the negative ion.
Sodium dihydrogen phosphate

13. Writing Formulas of Compounds that Contain Polyatomic Ions
Sodium phosphate

14. Write the Formula for Barium Nitrate

15. Write the Formula for Calcium Hydroxide

16. Write the Formula for Calcium chloride
Only put parentheses around polyatomic ions

17. Write the formula for ammonium carbonate