This document discusses polyatomic ions, which are positively or negatively charged groups of covalently bonded atoms. It provides examples of common polyatomic ions like ammonium, acetate, chlorate, and lists their formulas. It then outlines the steps to write formulas and name compounds that contain polyatomic ions, such as writing symbols and subscripts to balance charges and using a chart to identify polyatomic ion names in compound names.

1. Polyatomic Ion Compounds

2. Polyatomic Ions- positively or negatively charged covalently bonded group of atoms. The compound has 3 or more elements.

3. Polyatomic Ion Chart Name Formula +1 Ammonium NH 4 +1 -1 Acetate C 2 H 3 O 2 -1 Chlorate ClO 3 -1 Hydroxide OH -1 Nitrate NO 3 -1

4. Name Formula -2 Carbonate CO 3 -2 Sulfate SO 4 -2 -3 Phosphate PO 4 -3

5. Steps in Writing Formulas with Polyatomic Ions Write the symbol of the element/polyatomic ion that has a positive charge. Write the symbol of the element/ polyatomic ion that has a negative charge.

6. Write in subscripts so that the sum of the oxidation numbers equal zero. Enclosed with parenthesis (if needed).

7. Ex: Calcium Nitrate Ca +2 NO 3 -1 = Ca +2 (NO 3 -1 ) 2

8. Write the following formulas Sodium sulfate Magnesium chlorate Lithium acetate Barium carbonate Ammonium acetate Ammonium carbonate

9. Steps in Naming Compounds with Polyatomic Ion Write the name of the positive element. -If it’s an ammonium ion, write it first. 2. Use the polyatomic ion chart to find the name.

10. Ex: K 2 SO 4 = Potassium Sulfate

11. Name the following compounds Sr(OH) 2 C(NO 3 ) 4 BeCO 3 BPO 4 HC 2 H 3 O 2