* Calcium (Ca) has a +2 charge. This means each calcium atom loses two electrons.

* Chloride (Cl) has a -1 charge. This means each chlorine atom gains one electron.

To balance the charges, you need one calcium ion (Ca²⁺) to neutralize two chloride ions (2Cl⁻).

Here's the breakdown:

* +2 (Ca²⁺) + (-1) + (-1) (2Cl⁻) = 0