Final answer:
The valency of element X is 1, element Y is 2, and element Z is 0.
Step-by-step explanation:
The valency of an element is the number of chemical bonds it can form. For element X with atomic number 11, the valency would be 1 because it can form one chemical bond.
For element Y with atomic number 16, the valency would be 2 because it can form two chemical bonds.
And for element Z with atomic number 10, the valency would be 0 because it does not readily form chemical bonds.
Therefore, the correct order of elements with zero, one, and two valency is D) Z, Y, X.