It's important to clarify that the formula CaCl₂ refers to calcium chloride, not sodium chloride (NaCl). Let's break down why there are two chloride ions (Cl⁻) for every calcium ion (Ca²⁺) in CaCl₂.

Ionic Bonding and Charge Balance:

* Calcium (Ca) is a metal that tends to lose two electrons to achieve a stable electron configuration, becoming a positively charged ion (Ca²⁺).

* Chlorine (Cl) is a nonmetal that tends to gain one electron to achieve a stable electron configuration, becoming a negatively charged ion (Cl⁻).

Neutral Compound Formation:

For a compound to be stable, the total positive charge must equal the total negative charge. In CaCl₂:

* One calcium ion (Ca²⁺) has a +2 charge.

* Two chloride ions (2 Cl⁻) have a total of -2 charge.

Therefore, the 2:1 ratio of chloride ions to calcium ions ensures that the compound remains electrically neutral.

Note: The formula NaCl refers to sodium chloride (table salt), where one sodium ion (Na⁺) combines with one chloride ion (Cl⁻) to form a neutral compound.