Question

An element X is in group 2 of the periodic table What will be the formula of its chloride?

Answer 1

An element X in group 2 has a valency of 2. We know that chlorine has 7 valence electrons. Therefore, the valency of chlorine Cl is 1, that is, (8 - 7). 
Now, when one atom of X combines with two atoms of Cl, an ionic compound of the formula XCl₂ is formed.