Professor Kenneth W. Busch Rules for Assigning Oxidation Numbers 1.
Uncombined elements have a zero oxidation state.
Group VIIA elements are -1 in binary compounds. Sulfur is -2 in binary compounds. Balancing Redox Equations by the Half-Cell Method Reactions in Acidic Solution. Combine the two balanced half-reactions so that electron loss equals electron gain. Check the final result for mass and charge balance.