An element X belongs to Group 2 of the periodic table and possesses the highest first ionization enthalpy within its group. Element X exhibits a diagonal relationship with an element Y belonging to Group 13 . The identity of element Y is

Step-by-step solution

First ionization enthalpy decreases down a group due to an increase in atomic size. Therefore, the element with the highest first ionization enthalpy in Group 2 is Beryllium ( Be ). In the periodic table, the first element of Group 2 ( Be ) shows a diagonal relationship with the second element of Group 13 . Thus, Beryllium ( Be ) is diagonally related to Aluminum ( Al ). Hence, the element Y is Al . Answer: Al