Writing net ionic equations

Net ionic equations emphasize the chemical change by including only the species that are changed as a consequence of reaction.  The other species are known as spectator ions.

To write the net ionic equation for a precipitation reaction:
 

1. Use solubility rules to identify a precipitate (if any).
    
2. Write the formula of the precipitate produced at the right of an arrow.
    
3. Write the formulae for the ions that react to form that precipitate as reactants at the left of the arrow.
    
4. Add coefficients to balance atoms, making sure that the total charge at the left equals the total charge at the right.

Consider applying these steps to write the equation for the precipitation  reaction that occurs when potassium carbonate and silver nitrate are mixed.
 

1. Possible products:
   potassium nitrate and silver carbonate 
   
   Identify insoluble one:
   Silver carbonate is insoluble.
    
2. Precipitate formula:
                                      Ag₂CO₃(s)
3. Add reacting ions:
   Ag⁺(aq) + CO₃^2–(aq) Ag₂CO₃(s)
    
4. Balance:
   2Ag⁺(s) + CO₃^2–(aq) Ag₂CO₃(s)