Polyatomic Ionic Formulas

Polyatomic Ions + N H H H H What does NH4+ mean? Ion contains: 1 Nitrogen H H N Ion contains: 4 Hydrogens H H Overall Charge: +1

Symbols for Polyatomic Ions This charge applies to the ENTIRE ION Symbol: Ion Charge NH4 +

Writing Formulas – Equal Charges If the charge on the cation and anion are ________, drop the charges and put the two ions together equal Example) Al3+ PO43-  AlPO4

Polyatomic Ions – Unequal Charges Let’s just look at an example with a polyatomic ion. Write the ionic formula for: Barium Nitrate What’s the problem? How could we fix it?

Writing Ionic Formulas-Polyatomic Ions STEP EXAMPLE 1) Write the cation first, then the anion. Barium Nitrate Ba2+ NO3- Same as before

Writing Ionic Formulas – Polyatomic Ions STEP EXAMPLE 2) Put parenthesis ( ) around the polyatomic ion or ions. Leave the charge on the outside! Barium Nitrate Ba2+ (NO3)- New Step!!

Writing Ionic Formulas – Polyatomic Ions STEP EXAMPLE 3) Drop the + and – (but NOT the numbers!!) Barium Nitrate Ba2 (NO3)1 Same as before

Writing Ionic Formulas – Polyatomic Ions STEP EXAMPLE 4) Cross the charges. Leave the crossed charges on the outside!! Barium Nitrate Ba2 (NO3)1 Ba1(NO3)2 Same as before – with a twist!!

Writing Ionic Formulas – Polyatomic Ions STEP EXAMPLE 5) Drop any “1”. ALSO: If you drop a “1” for a polyatomic ion, you may also drop parenthesis ( ) Barium Nitrate Ba1(NO3)2 Ba(NO3)2 Same as before – with a twist!!

Another Look Ba(NO3)2 1 Ba 2 SETS of NO3 1 Ba 2 N 6 O What does this mean? Ba(NO3)2 1 Ba 2 SETS of NO3 1 Ba 2 N 6 O

Writing Ionic Formulas-Polyatomic Ions STEP EXAMPLE 1) Write the cation first, then the anion. Ammonium Phosphate NH4+ PO43- Same as before

Writing Ionic Formulas – Polyatomic Ions STEP EXAMPLE 2) Put parenthesis ( ) around the polyatomic ion or ions. Leave the charge on the outside! Ammonium Phosphate (NH4)+ (PO4)3- New Step!!

Writing Ionic Formulas – Polyatomic Ions STEP EXAMPLE 3) Drop the + and – (but NOT the numbers!!) Ammonium Phosphate (NH4)1 (PO4)3 Same as before

Writing Ionic Formulas – Polyatomic Ions STEP EXAMPLE 4) Cross the charges. Leave the crossed charges on the outside!! Ammonium Phosphate (NH4)1 (PO4)3 (NH4)3(PO4)1 Same as before – with a twist!!

Writing Ionic Formulas – Polyatomic Ions STEP EXAMPLE 5) Drop any “1”. ALSO: If you drop a “1” for a polyatomic ion, you may also drop parenthesis ( ) Ammonium Phosphate (NH4)3(PO4)1 (NH4)3PO4 Same as before – with a twist!!

Writing Ionic Formulas – Polyatomic Ions EXAMPLE Magnesium Hydroxide Mg2+ OH- Mg2+ (OH)- Mg2 (OH)1 Mg1(OH)2 Mg(OH)2

Writing Ionic Formulas – Polyatomic Ions EXAMPLE Lead (IV) Carbonate Pb4+ CO32- Pb4+ (CO3)2- Pb4 (CO3)2 Pb2(CO3)4 Pb(CO3)2

Writing Ionic Formulas – Polyatomic Ions EXAMPLE Silver Chlorate Ag+ ClO3- Notice: The cation charge is +1 and the anion is -1 AgClO3

(NH4)2O NH4+ O2- Ammonium Oxide Names – Example 1 (NH4)2O NH4+ O2- Ammonium Oxide

BaCrO4 Ba2+ CrO42- Barium Chromate Names – Example 2 BaCrO4 Ba2+ CrO42- Barium Chromate

Fe2(C2O4)3 Fe3+ C2O42- Iron (III) Oxalate Names – Example 3 Fe2(C2O4)3 Fe3+ C2O42- Iron (III) Oxalate

K3PO4 K+ (PO4)3- Potassium phosphate Names – Example 4 K3PO4 K+ (PO4)3- Potassium phosphate

Group Practice Ionic Formulas and Names – Polyatomic Ions – Group Practice

Group Practice - Check Station Cation Anion Ionic Formula Ionic Name 1 Aluminum CO32- 2 NH4+ PO43- 3 Ba2+ Nitrate 4 Iron (III) SO32- 5 Li+ BrO3- 6 Nitride

Group Practice - Check Station Cation Anion Ionic Formula Ionic Name 7 Cu2+ CO32- 8 Al3+ Phosphate 9 Pb2+ OH- 10 Pb4+ SO32-

Group Practice - Check Station Cation Anion Ionic Formula Ionic Name 1 Al3+ CO32- Al2(CO3)3 Aluminum carbonate 2 NH4+ PO43- (NH4)3PO4 Ammonium Phosphate 3 Ba2+ Nitrate Ba(NO3)2 Barium Nitrate 4 Iron (III) SO32- Fe2(SO3)3 Iron (III) Sulfite 5 Li+ BrO3- LiBrO3 Lithium Bromate 6 N3- (NH4)3N Ammonium nitrate

Group Practice - Check Station Cation Anion Ionic Formula Ionic Name 7 Cu2+ CO32- CuCO3 Copper (II) Carbonate 8 Al3+ PO43- AlPO4 Aluminum Phosphate 9 Pb2+ OH- Pb(OH)2 Lead (II) Hydroxide 10 Pb4+ SO32- Pb(SO3)2 Lead (IV) Sulfite

Group Practice - Check (NH4)3N Ammonium Nitrate FeSO3 Iron(II) Sulfite Fe2(SO3)3 Iron(III) Sulfite KNO3 Potassium Nitrate Cd3(BO3)2 Cadmium Borate

Independent Practice Ionic Formulas and Names – Polyatomic Ions – Individual Practice Let me know if you have any questions!!!