An unknown compound was discovered to have the formula X2O3, where O stands for oxygen. What is the ion charge of the unknown element X?

Explanation:

The valency of element is 3 and formula of its chloride is XCL_3XCL

3

Explanation: The neutral oxide of the element X , X_2O_3X

2

O

3

is formed by the combination of X^{3+}X

3+

and O^{2-}O

2−

. Thus the valency of the element is X as it has lost three electrons to acquire stable noble gas configuration.

Similarly oxygen has gained two electrons to attain stable noble gas configuration and thus has a valency of two.

The chloride of the element X is formed by combination of X^{3+}X

3+

and Cl^{-}Cl

−

and thus to form a neutral compound XCl_3XCl

3

is formed.