How to Balance Redox Reaction by Ion - Electron Method: Cu + HNO3 → Cu(NO3)2 + H2O + NO2 (copper)

In the ion-electron method (also called the half-reaction method), the redox equation is separated into two half-equations - one for oxidation and one for reduction. Each of these half-reactions is balanced separately and then combined to give the balanced redox equation. Cu + HNO3 → Cu(NO3)2 + H2O + NO2