A student is given the following ions and their valencies:
 
Ion Valency
\(Na^{+}\) \(1\)
\(Mg^{2+}\) \(2\)
\(Al^{3+}\) \(3\)
\(Cl^{-}\) \(1\)
\(O^{2-}\) \(2\)
\(S^{2-}\) \(2\)
 
The student has to write the correct chemical formulae of compounds formed by these ions.
 
Identify the correct chemical formula:
Write the formula of the compound formed by \(Mg^{2+}\) and \(Cl^{-}\).