Given the reactions:

2 X(s) + 2 H2O() → 2 X+(aq) + 2 OH–(aq) + H2(g)
2 Y(s) + 2 H2O() → 2 Y+(aq) + 2 OH–(aq) + H2(g)

The unknowns, X and Y, are most likely

A) metallic elements in the same group
B) metallic elements in the same period
C) nonmetallic elements in the same group
D) nonmetallic elements in the same period

The unknowns, X and Y elements are most likelyto be metallic elements belonging to same group. Thus, option A is correct.

The metals are elements in the periodic table that have the tendency to lose electrons and form positive ions. The periodic table has been the arrangement of elements in group and periods.

The elements belonging to same group have similar chemical properties, as they have same number of valence electrons.

The given reaction results in the formation of same byproducts with equivalent ion formation.

The ions for the reaction has a positive charge with the loss of electrons from the atom.

Since, X and Y loses electrons and have similar chemical properties, the elements are likely to be metallic elements belonging to same group. Thus, option A is correct.

For more information about metallic elements, refer to the link:

link

A) metallic elements in the same group

Explanation:

X and Y are are group one elements called Alkali metals that react with water to displace hydrogen gas.They have large electrode potential thus they are oxidized to form a metal ion while the water is reduced to hydroxide ions and hydrogen gas.The solution formed is a basic solution and the reaction is exothermic.Note that the reaction of Alkali metals with water is violently and explosively.