The element has 7 different stable oxides, all of which are acidic. In the lower oxide, the mass fraction of oxygen

The element has 7 different stable oxides, all of which are acidic. In the lower oxide, the mass fraction of oxygen is 18.4 percent. Determine the unknown element and the mass fraction of oxygen in the higher oxide. Write the equations for the reactions of higher and nothing oxide with water.

In the lower oxide, the unknown element has a minimum oxidation state, therefore, such a molecule consists of one oxygen atom and two atoms of the desired element. We calculate the mass of the oxide molecule:

16 / (18.4 / 100) = 87.

Then the atomic weight of the element will be:

(87 – 16) / 2 = 35.5.

According to the periodic table, we find that it is chlorine.

Cl2O + H2O = 2HClO;

Cl2O7 + H2O = 2HClO4.

The oxygen concentration in the higher oxide will be:

(16 * 7/183) * 100 = 61.202%.