The net ionic equation is an equation that shows only the ions that participate in a chemical reaction. It focuses on the ions that actually undergo a change during the reaction, ignoring the spectator ions that do not change.
To write a net ionic equation:
1. Start with the balanced molecular equation for the reaction.
2. Write the chemical formulas for all soluble ionic compounds as dissociated ions.
3. Identify and eliminate the spectator ions (ions that appear on both sides of the equation unchanged).
4. Write the remaining ions to form the net ionic equation.
For example, consider the reaction between silver nitrate (AgNO3) and sodium chloride (NaCl) to form silver chloride (AgCl) and sodium nitrate (NaNO3):
- The balanced molecular equation is AgNO3 + NaCl → AgCl + NaNO3.
- When written as ions, it becomes Ag+ + NO3- + Na+ + Cl- → AgCl + Na+ + NO3-.
- Spectator ions are Na+ and NO3-, which do not change during the reaction.
- The net ionic equation is Ag+ + Cl- → AgCl.
In summary, the net ionic equation focuses on the essential ions involved in a reaction, stripping away the spectator ions to highlight the core chemical changes occurring in the process.
