The charge on the metal ion is 2+. The metal is magnesium.
The metal ion is ##”Mg”^(2+)”##. Magnesium sulfate, ##”MgSO”_4″##, is an ionic compound composed of Magnesium ##2^+## cations, and sulfate ##2^-## anions, ##”SO”_4″”^(2-)”##.
##”Mg”^(2+)”+ SO”_4″”^(2-)”####rarr####”MgSO”_4″##
