Question

write the formula for the following ionic compound: magnesium phosphate (containing the $\text{po}_{4}^{3-}$ ion)

Explanation:

Step1: Determine the charge of magnesium ion

Magnesium (\(Mg\)) is in group 2 of the periodic table. So, the magnesium ion has a charge of \(Mg^{2 +}\).

Step2: Use the criss - cross rule

For an ionic compound, the sum of the charges of cations and anions must be zero. Let the formula be \(Mg_x(PO_4)_y\). Using the charge balance: \(2x-3y = 0\). The smallest non - zero integers \(x = 3\) and \(y = 2\) satisfy this equation.

Answer:

\(Mg_3(PO_4)_2\)