(a) The element X has 2 valence electrons because it belongs to group 2.
(b) Since the number of valence electrons and the valency of group 2 elements is 2, the valency of element X is 2.
(c) Group 2 is on the left side of the periodic table which consists of metals. Therefore X is a metal.
(d) The name of the element is Magnesium (Mg), since X belongs to group 2 and the 3rd period.