Element X forms a chloride with the formula XCl 2 , which is a solid with a high melting point. X would most likely be in the same group of the Periodic Table as
(a) Na (b) Mg (c) Al (d) Si
the answer is Mg . Why?
because Mg has the valency 2, and valency in a group remains the same...Also, when it combines with Clorine (having valency 1)..it forms MgCl2
Na has valency 1
Al has valency 3
Si has valency 4