Net Ionic Equations

Because reactions such as displacements often involve ions in solution, they can be written in ionic
form. In the example where zinc is reacted with copper sulfate, the ionic equation would be:

Zn  (s) +   Cu2+    (aq)    +   SO 4 2– (aq)    →   Cu  (s) +   Zn2+    (aq)    +   SO 4 2– (aq)

When displacement reactions occur, there are usually spectator ions that do not take part in the
overall reaction but simply remain in solution throughout. The spectator ion in the equation above
is sulfate, which does not undergo any transformation during the reaction. A net ionic reaction can
be written showing only the species that actually participate in the reaction:

Zn  (s) +   Cu2+    (aq)    →   Cu  (s) +   Zn2+    (aq)

Net ionic equations are important for demonstrating the actual reaction that occurs during a
displacement reaction.