Final answer:
Element X likely has a valency of 3, and if it has 5 valence electrons, it could be an element from group 15. Element Y's valency would depend on its ability to form covalent bonds with Z, and the number of covalent bonds in a molecule varies by the elements' valencies and needs to fulfill their outer electron shells.
Step-by-step explanation:
The question asks about the properties of elements V, W, X, Y, and Z. Without specific periodic table context or names, we can try to infer based on general chemical principles.
Element X is said to have 5 valence electrons, which suggests it could belong to group 15 of the periodic table. The valency of an element is its ability to combine with other atoms when forming chemical compounds; for element X, with 5 valence electrons, it typically has a valency of 3 as it tends to form three covalent bonds to reach a stable electron configuration, resembling the noble gases.
Regarding element Y, if Y and Z form a covalent bond, both typically have valency that allows them to share electrons to achieve stability. Without specific details, it's difficult to suggest names for X and Y, but following periodic trends, potential candidates for X could be nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), or bismuth (Bi); as for Y, it would depend on the specifics of the covalent bond with Z.
When looking at covalent bonds in a molecule, the number of bonds depends on the elements involved and their valency, which informs us how many bonds they must form to complete their outer electron shells.