Iv. balance the charge in the half-reactions. (.5 point)

Balance the number of atoms of the key element on both sides. Add the appropriate number of electrons to compensate for the change of oxidation state. Add H+(in acid medium), or OH- (in basic medium), to balance the charge on both sides of the half-reactions; and H2O, if necessary, to balance the equations.

Idont know. if you want an answer you need to give us some context dude.