Ionic Compounds with Polyatomic Ions Chemistry Part 8 Ionic Compounds with Polyatomic Ions

Polyatomic Ions An ion made up of 2 or more different atoms. Covalent (non-ionic) bonds are between the atoms. The charge belongs to the entire ion. Names end in “ate” or “ite”. See the back of your periodic table.

Polyatomic Ions Examples: Ammonium (only one with a positive charge) NH41+ The charge is for the entire compound. Phosphate PO43- Phosphite PO33-

Formula Writing Same process as before, but the polyatomic ion must be placed in brackets if it requires a subscript (more than one).

Formula Writing Example: Magnesium nitrate Mg  2+ NO3  1- Mg(NO3)2

Formula Writing Example: Iron (II) sulfate Fe  2+ SO4  2- FeSO4

Formula Writing Example: Ammonium sulfide NH41+ and S2- (NH4)2S

Formula Writing Example: Iron (II) nitrate Pb2+ and NO31- Pb(NO3)2

Nomenclature Write the name of the metal (cation) If it is a transition metal, follow those rules. Write the name of the polyatomic ion.

Nomenclature Example: NaNo3 Sodium nitrate Ca(OH)2 Calcium hydroxide

Nomenclature Example: Fe(OH)3 1- Iron must have a 3+ charge Iron (III) hydroxide 1- 1- 1-

Nomenclature Example: CuSO4 2- Copper must have a 2+ charge Copper (II) sulfate 2-

Nomenclature Example: (NH4)2SO4 Ammonium sulfate

Practice Worksheet Page 127 # 17, 18