Lawrence A. answered 11/04/12
A fully & highly qualified chemistry teacher with GaPSC
A stable compound usually has an oxidation number of zero.This is because they must have exchanged and balanced their oxidation numbers which is also called the combining power of their ions.Hence Potassium (K)Chloride(Cl) KCl has oxidation number of zero.
K has +1 combining power and Cl has -1 combining power ,since the addition of the two combining power +1 and -1 equals zero,the compound is a stable one .
Therefore, K +1 + Cl-1 ----------> KCl +1-1 (KCl)0
Thus the charge on K in KCl is +1