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Ch. 15 and 6 Polyatomic Ions. Polyatomic Ions . Tightly bound groups of atoms that behave as a unit and carry a charge. Examples:. Ammonium NH 4 +. Cyanide CN -. Sulfite SO 3 2-. Common Polyatomic Ions with a -1 charge. ClO -1 hypochlorite ClO 2 -1 chlorite
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Polyatomic Ions Tightly bound groups of atoms that behave as a unit and carry a charge. Examples: Ammonium NH4+ Cyanide CN- Sulfite SO32-
Common Polyatomic Ionswith a -1 charge • ClO-1 hypochlorite • ClO2-1 chlorite • ClO3-1 chlorate • ClO4-1 perchlorate • CN-1 cyanide • MnO4-1 permanganate • NO3-1 nitrate • NO2-1 nitrite
-1 polyatomic ions cont. • OH-1 hydroxide • HCOO-1formate • HCO3-1 hydrogen carbonate or bicarbonate • HSO3-1 hydrogen sulfite • HSO4-1 hydrogen sulfate • CH3COO-1 or C2H3O2-1 acetate
-2 polyatomic ions • C2O4-2 oxalate • CO3-2 carbonate • Cr2O7-2 dichromate • CrO4-2 chromate • SO4-2 sulfate • SO3-2 sulfite
-3 polyatomic ion • PO4-3 phosphate • PO3-3 phosphite
+1 polyatomic ions • NH4+1 ammonium • H3O+1 hydronium
Polyatomic Ions • Examine Relationships • Most end in –ite / -ate Trick to remember: The bigger number ate the little number! SO42- Sulfate SO32- Sulfite
The big number ate the little number! PO43- Phosphate NO3- Nitrate PO33- Phosphite NO2- Nitrite
Writing Formulas for Ternary Ionic Compounds A. Contain a polyatomic ion B. Same rules as for binary ionic compounds. One addition – Use parenthesis if there is more than one polyatomic ion • Examples: • Calcium Hydroxide • Calcium - Ca2+ OH- –Hydroxide • Formula for compound – Ca(OH)2
Boron acetate B3+ C2H3O2-1 B(C2H3O2)3 Magnesium Dichromate Mg+2 Cr2O7-2 Mg2(Cr2O7)2 MgCr2O7
Examples (cont.) • Magnesium Nitrate • Magnesium – Mg2+ • Nitrate - ???? • Write the formula for the compound
Practice Problems Write formulas for the following ternary ionic compounds: • Calcium Carbonate • Potassium Sulfate • Barium Nitrite • Magnesium Phosphate CaCO3 K2SO4 Ba(NO2)2 Mg3 (PO4)2
Naming Ternary Ionic Compounds • Same rules as for naming binary ionic compounds: • Name the cation – Use a Roman numeral if necessary • Name the anion • Do not use the word “ion” in the compound name
Practice Problems: • Name the following ternary ionic compounds: • NaCN • KClO • Li2SO3 • CaC2O4 • Al(OH)3 • Sn3(PO4)2 Sodium cyanide Potassium hypochlorite Lithium sulfite Calcium oxalate Aluminum hydroxide Tin (II) phosphate
Ionic Compounds- Polyatomic IonsDue at the end of class, Completed -1 -1 -2 -3 -1 + + +2