Complete Ionic and Net Ionic Equations
Writing Complete Ionic Equations
1. Start with the Balanced Molecular Equation
Ex.
2 Na3PO4 (aq) + 3 CaCl2 (aq) → 6 NaCl (aq) + Ca3(PO4)2 (s)
2. Break all soluble substances (anything with (aq) next to them) into their ions. Leave all compounds with (s), (l),
or (g) the same.
a. Indicate the correct formula and charge of each ion
b. Indicate the correct number of each ion by using coefficients in front of the ions
c. Write (aq) after each ion
*Complete (Total) Ionic Equation: 6 Na+ aq) + 2 PO43- (aq) + 3 Ca2+ (aq) + 6 Cl- (aq) → 6 Na+ (aq) + 6 Cl- (aq) + Ca3(PO4)2 (s)
Writing Net Ionic Equations
Spectator ions:
 Ions that are present in the reaction mixture but do not participate in it.
 They "sit around and watch the reaction take place"
 You can recognize spectator ions by looking for ions that are present on both sides of the equation.
 They will always have the same exact formula, charge, and physical state. They will also be present in exactly the
same number on both sides of the equation.
To write a net ionic equation:
1. Write the balanced molecular equation.
2. Write the balanced complete ionic equation.
3. Cross out the spectator ions that are present.
4. Write the "leftovers" as the net ionic equation.
Ex. Cross out spectator ions
6 Na+ (aq) + 2 PO43- (aq) + 3 Ca2+ (aq) + 6 Cl- (aq) → 6 Na+ (aq) + 6 Cl- (aq) + Ca3(PO4)2 (s)
and then re-write the "leftovers:"
*Net Ionic Equation: 2 PO43- (aq) + 3 Ca2+ (aq) → Ca3(PO4)2 (s)
Practice Problems Part 1: Write the Complete (Total) Ionic and Net Ionic Equations for each of the following Balanced
Molecular Equations
1. Balanced Molecular Equation: 3 (NH4)2CO3 (aq) + 2 Al(NO3)3 (aq)→ 6 NH4NO3 (aq) + Al2(CO3)3 (s)
Complete Ionic Equation: ___________________________________________________________________
Net Ionic Equation: ________________________________________________________________________
2. Balanced Molecular Equation: 2 NaOH (aq) + H2SO4 (aq) --> Na2SO4 (aq) + 2 H2O (l)
Complete Ionic Equation: ______________________________________________________________________
Net Ionic Equation: ___________________________________________________________________________
3. Balanced Molecular Equation: Pb(NO3)2 (aq) + 2 KCl (aq) 
PbCl2 (s) + 2 KNO3 (aq)
Complete Ionic Equation: ______________________________________________________________________
Net Ionic Equation: ___________________________________________________________________________
Practice Problems Part 2:
a. Predict the products (including whether they are aqueous or solid) and write the Balanced Molecular Equation
b. Write the Complete Ionic Equation
c. Write the Net Ionic Equation
4. Balanced Molecular Equation:
K3PO4(aq)
+
Al(NO3)3
→
Complete Ionic Equation: __________________________________________________________________
Net Ionic Equation: ________________________________________________________________________
5. Balanced Molecular Equation:
NaCl (aq) +
Pb(NO3)2
→
Complete Ionic Equation: ___________________________________________________________________
Net Ionic Equation: ________________________________________________________________________
6. Balanced Molecular Equation:
Na2CO3 (aq)
+
FeCl2 (aq) →
Complete Ionic Equation: __________________________________________________________________
Net Ionic Equation: _______________________________________________________________________