# Why is the chemical formula for magnesium chloride "MgCl"_2"?

Aug 16, 2017

Since Mg needs to lose two valence electrons, it is required that two Cl atoms each gain one Mg valence electron. The Mg atom becomes a $\text{Mg"^(2+)}$ ion and each Cl atom becomes a $\text{Cl"^(-)}$ ion. The ionic bond is the electrostatic attraction between oppositely charged ions.