Answer:
X₂O₃ , Y₂O
Step-by-step explanation:
Valency of an element tells how well that element can form compounds with other atoms.
It sometimes, is also determined by the number of hydrogen atoms that it combines with.
Oxygen usually has a valency of 2, or oxidation state of -2.
That means oxygen will need 2 more electrons in it's outer shell to form a configuration of a noble gas(octet configuration).
The oxidation state of an atom in a molecule gives the number of valence electrons it has gained or lost.
Assuming both X and Y are less electronegative than oxygen, X has a valency of 3 and OS of +3.
While forming a neutral compound, we need no net charge on the compound. In X₂O₃,
total charge on X is 2 x (OS of X)= 2 x ( +3) = +6
total charge on O is 3 x (OS of O)= 3 x ( -2) = -6
Net charge is 0.
Similarly, in Y₂O
total charge on Y is 2 x (OS of Y)= 2 x ( +1) = +2
total charge on O is 1 x (OS of O)= 1 x ( -2) = -2
Net charge is 0.