1. The problem statement, all variables and given/known data Potassium chromate is an important compound of chromium. It is composed of K+ and CrO42-. Write the formula of the compound. 2. Relevant equations positive charge + negative charge = 0 3. The attempt at a solution I know how to do this problem by cross switching the charges but I want to know how to do it by finding the ratio. So what I tried to do was say that it takes 8 K to equal the negative charge of the CrO4 so the ration is 8:4. That means K8 = CrO4. Then I reduced and got K2 = CrO. The correct answer is K2 = CrO4.