Polyatomic Ions polyatomic ion: tighlty bonded group of atoms with a + or – charge overall N N P S O OO O O O O O O O O H H H H

Common Polyatomic Ions NameFormulaCharge ammoniumNH hydroxideOH – 1– acetateC2H3O2–C2H3O2– 1–1– permanganateMnO 4 – 1–1– nitrateNO 3 – 1–1– chlorateClO 3 – 1–1– bicarbonateHCO 3 – 1–1– carbonateCO 3 2 – 2–2– sulfateSO 4 2 – 2–2– phosphatePO 4 3 – 3–3–

nitridenitrate N 3– NO 3 – chloridechlorate Cl – ClO 3 – sulfidesulfate S 2– SO 4 2– phosphidephosphate P 3– PO 4 3– MonatomicPolyatomic ammonium NH 4 + hydroxide OH – all end in –ide typically end in –ate (most have O’s)

Same rules as with all compounds. Example: calcium nitrate 1.symbols of ions 2.charges (as superscripts) 3.crisscross (to get subscripts) 4.erase charges 5.use ( ) for multiple polyatomic ions Ca 2+ NO 3 – Names and Formulas for Compounds with Polyatomic Ions Ca NO 3 Ca 2+ NO 3 – CaNO 32 ? Ca(NO 3 ) 2

Write the formulas for the following compounds with polyatomic ions. (use your polyatomic ions sheet) 1.ammonium nitrate 2.calcium phosphate 3.iron(III) carbonate Ca 2+ PO 4 3– Fe 3+ CO 3 2– NH 4 + NO 3 – NH 4 NO 3 Ca 3 (PO 4 ) 2 Fe 2 (CO 3 ) 3

1.Which of the following are positively charged polyatomic ions? 1) ammonium ion 2) nitrate ion 3) iron(III) ion A.1 only B.2 only C.1 and 2 D.1 and 3 Quick Quiz! NH 4 + NO 3 – Fe 3+

2. What is the correct name for Mg(OH) 2 ? A.magnesium oxide B.magnesium hydroxide C.magnesium(II) hydroxide D.magnesium(II) hydroxate Quick Quiz.

3.What is the correct formula for copper(I) sulfate? A.CuS B.CuSO 4 C.Cu 2 SO 4 D.Cu(SO 4 ) 2 Cu + SO 4 2– Quick Quiz.

4.Which one of the following formulas is named correctly? A.sodium bicarbonate, Na 2 CO 3 B.potassium nitrate, KNO 2 C.sodium acetate, NaC 2 H 3 O 2 D.lithium sulfide, Li 2 SO 4 Quick Quiz.