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 + -3 Li and AsO4 Li3AsO4 Beryllium and Arsenate +2 -3 Be and AsO4 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! - -2 - - - C2H3O2 CO3 ClO3 OH NO3 Li+ (1) (2) Mg+2 (3) (4) Ga+3 (5) (6) + Rb (7) (8) In+3 (9) (10) NH + 4 (11) (12) 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 ___________ 2. Beryllium Arsenite ___________ 3. Sodium Bicarbonate ___________ 4. Magnesium Bisulfate ___________ 5. Aluminum Bisulfite ___________ 6. Potassium Borate ___________ 7. Calcium Chlorite ___________ 8. Gallium Chromate ___________ 9. Rubidium Cyanate ___________ 10. Strontium Cyanide ___________ 11. Indium Dichromate ___________ 12. Cesium Ferricyanide ___________ 13. Barium Ferrocyanide ___________ 14. Thallium Hypochlorite ___________ 15. Ammonium Oxalate ___________ 16. Ammonium Perchlorate ___________ 17. Lithium Peroxide ___________ 18. Beryllium Silicate ___________ 19. Sodium Sulfite ___________ 20. Magnesium Thiosulfate ___________ 21. Aluminum Arsenate ___________ 22. Potassium Bisulfate ___________ 23. Calcium Bisulfite ___________ 24. Gallium Borate ___________ .