The formula for the oxide in this case can be determined by using the information provided. Since the oxidation state of the element is +2, the formula for the oxide can be calculated by considering the charge balance.

The oxidation state of oxygen is typically -2. Since there is a 50% oxygen in the compound, the overall charge of oxygen in the compound is equal to (-2)(50%) = -1.

For the compound to be neutral, the overall charge of the cation (in this case, the element with a +2 oxidation state) must balance with the overall charge of the anion (in this case, the oxygen with a -1 charge).

So, the formula for the oxide would be MO, where M represents the element with the +2 oxidation state.