7.1.2 Balancing redox equations using ion-electron method The principles of balancing redox equations: 1 charge balance:the sum of the electrons gained by oxidizing agent equals the sum of the electrons lost by reducing agent. 2 mass balance:the number of the atoms before the redox reaction occurs is equal to that of the atoms when the reaction is finished. The principles of balancing redox equations: ① charge balance:the sum of the electrons gained by oxidizing agent equals the sum of the electrons lost by reducing agent. ② mass balance: the number of the atoms before the redox reaction occurs is equal to that of the atoms when the reaction is finished. 7.1.2 Balancing redox equations using ion-electron method