Element X forms a chloride with the formula XCl₂, which is a solid with high melting point. X would most likely be in the same group of periodic table as

The formula XCl₂ indicates that X has a valency of +2, which corresponds to Group 2 elements (alkaline earth metals). The fact that XCl₂ is a solid with a high melting point indicates it is an ionic compound, which is characteristic of Group 2 metal chlorides like MgCl₂ and CaCl₂. Magnesium (Mg) is a Group 2 element, so X would most likely belong to the same group as Mg. Na and K are Group 1 elements with +1 valency (forming XCl), and Al is a Group 13 element with +3 valency (forming XCl₃).