4. Number of electrons gained must equal the number of electrons lost.
- Find the least common multiple of the electrons gained and lost.
- In each half-reaction, multiply the electron coefficient by a number to reach the common multiple.
- Multiply all of the coefficients in the half-reaction by this same number.
5. Add the two half-reactions.
- Write one equation with all the reactants from the half-reactions on the left and all the products on the right.
- The order in which you write the particles in the combined equation does not matter.
6. Simplify the equation.
- Cancel things that are found on both sides of the equation as you did in net ionic equations.
- Rewrite the final balanced equation.
7. Check the equation.
- There should be no electrons in the equation at this time.
- The number of each element should be the same on both sides.
- It doesn't matter what the charge is as long as it is the same on both sides.
- If any of these are not balanced, the equation is incorrect. The only thing to do is go back to step #1 and begin looking for your mistake.