X has an atomic number of 11 and hence it's sodium (Na) while Y has an atomic number of 3 and hence it is Lithium (Li).
The atomic mass of X is 23 while that of Y is 7
X has three electron shells while Y has two electron shells
X and Y cannot form a compound as there ions are both positively charged (cations). However, there ions both have a charge of +1; hence are univalent positive metals.
They are both metals and are found in group 1 of the periodic table
The are highly reactive metals because they have just one electron in there outermost shell
