Ionic Bonding Part 2-Polyatomics
Polyatomic ions are ____________________ of elements (poly = many) that are covalently bonded together and
have an overall ____________________ charge.
When forming a compound, polyatomic ions work as a ____________________. So after criss-crossing the
charges, it will be necessary to use parentheses if the subscript is bigger than ____________________.
Examples: Lithium and Arsenate
Li+ and AsO4 -3
Li3AsO4
Beryllium and Arsenate
Be+2 and AsO4 -3
Be3(AsO4)2
When naming ionic compounds with polyatomic ions, the polyatomic ion already has a special name that
____________________ changes.
Examples:
LiC2H3O2 = lithium ____________________
NH4OH = ____________________ hydroxide
If the ending is a normal nonmetal, still change the ending to “ide”!
Exercise 4:
In the following grids:
1) Criss-cross the metal or ammonium and polyatomic ion in the appropriate. Use parentheses on the
polyatomic ions when necessary.
2) Reduce if possible!
C2H3O2
-
CO3
-2
ClO3
-
OH
-
NO3
+
Li
(1)
(2)
+2
Mg
(3)
+3
Ga
Rb
In
(4)
(5)
+
(6)
(7)
+3
NH4
(9)
+
(11)
(12)
(10)
(8)
-
Naming Ionic Compounds with Polyatomic Ions
Determining the name of an ionic compound with a polyatomic ion is even easier as the name of the polyatomic
ion NEVER changes.
Examples:
LiC2H3O2 = lithium acetate
NH4OH = ammonium hydroxide
Notice that the subscripts still have no effect on the name of the ionic compounds.
Exercise 5:
For each of the compounds made in the grids in exercise 4, write the name of the compounds.
1. _________________________________
2. _________________________________
3. _________________________________
4. __________________________________
5. __________________________________
6. __________________________________
7. __________________________________
8. __________________________________
9. __________________________________
10. _________________________________
11. _________________________________
12. _________________________________
Writing Ionic Compound Formulas from their Names
When given the name of the ionic compound that includes a polyatomic ion, the same basic steps for naming a
binary ionic compound apply:
1) Write the symbols for the metal or ammonium and the polyatomic ion.
2) Figure out the charge on each.
3) Criss-cross the charges and reduce. Don’t forget to use parentheses if necessary.
Exercise 6:
For each of the following named ionic compounds, write the correct formula. Be sure to follow all the steps
presented above.
1. Lithium Arsenate
3. Sodium Bicarbonate
5. Aluminum Bisulfite
7. Calcium Chlorite
9. Rubidium Cyanate
11. Indium Dichromate
13. Barium Ferrocyanide
15. Ammonium Oxalate
17. Lithium Peroxide
19. Sodium Sulfite
21. Aluminum Arsenate
23. Calcium Bisulfite
___________
___________
___________
___________
___________
___________
___________
___________
___________
___________
___________
___________
2. Beryllium Arsenite
4. Magnesium Bisulfate
6. Potassium Borate
8. Gallium Chromate
10. Strontium Cyanide
12. Cesium Ferricyanide
14. Thallium Hypochlorite
16. Ammonium Perchlorate
18. Beryllium Silicate
20. Magnesium Thiosulfate
22. Potassium Bisulfate
24. Gallium Borate
___________
___________
___________
___________
___________
___________
___________
___________
___________
___________
___________
___________