What is the most likely formula for the oxide of this element?

Question

The formula for the chloride of a certain element is XCl2.

A) XO₃

B) X₂O₃

C) X₃O₂

D) XO

I think it's C, is that right?

Answer 1

From the formula XCl₂, you can tell that X must have an oxidation number of 2+ since each Cl is 1-. We know that in oxides, O has an oxidation number of 2-, so the oxide of X would be XO (choice D).

Answer 2

Answer is D— The most likely formula for the oxide would be XO