Naming Ionic Compounds Contains these elements: 1 Metal and 1 Nonmetal Rules: Cation is written first - Capitalize If it is a metal with multiple ions (most transition metals), include a Roman Numeral Anion is written second- lowercase (Remember the ending of the anion is changed to-ide)

You try… K3 N Mg O Challenge: SnO2 Examples: Li Br Lithium bromide Fe Cl2 Iron (II) chloride You try… K3 N Potassium nitride Mg O Magnesium oxide Challenge: SnO2 Tin (IV) oxide

Polyatomic ion Polyatomic ion – a molecular compound with a charge due to missing or extra electrons

Polyatomic Ions Hydronium H3O+ Hydroxide OH- Acetate C2H3O2- Nitrate NO3- Cyanide CN- Chlorate ClO3- Sulfate SO42- Carbonate CO32- Phosphate PO43- Ammonium NH4+

Writing formulas Write the cation and anion formulas Magnesium phosphate Mg2+ PO43- Draw parenthesis around the polyatomic ion with charge on outside Mg2+ (PO4)3- Use criss-cross to bring charges down Write ionic formula Mg3(PO4)2