* Calcium (Ca) is in group 2 of the periodic table, meaning it has a +2 charge as a cation (Ca²⁺).
* Chlorine (Cl) is in group 17 of the periodic table, meaning it has a -1 charge as an anion (Cl⁻).
To form a neutral compound, you need two chlorine ions (2 x -1 = -2) to balance the +2 charge of the calcium ion.
