Formulas, Names, and Masses of Compounds (Sample Problems 27 to 216) Concept Review Questions What information about the relative numbers of ions and the percent mass of elements is in the formula MgFZ?

MgF₂ = Mg⁺² + 2F⁻¹.

Relative number of ions of Mg⁺² and F⁻¹ in the salt is 1 : 2.

Total molar mass = 62.0g.

molar mass of Mg = 24g and molar mass of F is 19 g, So two atoms = 19 x 2 = 38 g.

So in 62.0 g of MgF₂ the mass of Mg is 24 g

Percentage of Mg is 24 / 62.0 x 100 = 38.7 %

Percentage of F = 38/62.0 X 100 = 61.2%