Final answer:
Element X is divalent and can form two bonds, while element Y is tetravalent and can form four bonds, suggesting the formation of a compound with a 1:2 ratio, represented by XY2. Specifying exact elements for X and Y like magnesium and carbon could yield a compound like MgC2.
Step-by-step explanation:
The question involves understanding how the valency of elements affects the formation of chemical compounds. Element X is divalent, meaning it has a valency of 2 and can form two bonds. Element Y is tetravalent, with a valency of 4, implying it can form four bonds. In order to obey the rule that the total number of electrons lost by one element must equal the total number gained by the other, a stable compound would have a formula XY2. This is because each atom of X will form two bonds, and since Y can form four, it would need two X atoms to satisfy its valency requirements. This results in a 1:2 ratio of Y to X atoms in the compound.
Examples of elements that could represent X and Y could be magnesium (Mg) for X, which is a commonly known divalent metal, and carbon (C) for Y, which is a well-known tetravalent non-metal. Therefore, the compound could be MgC2 if we were specifically discussing these elements. However, without more specific information on the identity of elements X and Y, we cannot assert the exact chemical compound they would form or its precise properties.