Answer: Option (b) is the correct answer.
Step-by-step explanation:
It is known that when we write a chemical formula then the subscript present in it represents the number of atoms of an element are participating in the chemical bonding.
For example, as the given compound is
.
So here, no subscript is present on magnesium atom which means that its subscript is 1 and chlorine atom has a subscript 2 which means that there are 2 atoms of chlorine are present in
.
Therefore, we can conclude that the subscript 2 indicate in the compound
that there are 2 chloride ions for each magnesium ion.