Questions: Write the empirical formula of at least four binary ionic compounds that could be formed from the following ions: Mg^2+, Cr^4+, Br^-, S^2-

Solution Steps

To form binary ionic compounds, we need to pair each cation with an anion. The cations given are \(\mathrm{Mg}^{2+}\) and \(\mathrm{Cr}^{4+}\), and the anions are \(\mathrm{Br}^{-}\) and \(\mathrm{S}^{2-}\).

For each cation-anion pair, balance the charges to form a neutral compound:

1. \(\mathrm{Mg}^{2+}\) and \(\mathrm{Br}^{-}\):

   • The charge on \(\mathrm{Mg}^{2+}\) is +2, and the charge on \(\mathrm{Br}^{-}\) is -1.
   • To balance the charges, we need two \(\mathrm{Br}^{-}\) ions for every \(\mathrm{Mg}^{2+}\) ion.
   • Empirical formula: \(\mathrm{MgBr}_2\).

2. \(\mathrm{Mg}^{2+}\) and \(\mathrm{S}^{2-}\):

   • The charge on \(\mathrm{Mg}^{2+}\) is +2, and the charge on \(\mathrm{S}^{2-}\) is -2.
   • The charges are already balanced with one of each ion.
   • Empirical formula: \(\mathrm{MgS}\).

3. \(\mathrm{Cr}^{4+}\) and \(\mathrm{Br}^{-}\):

   • The charge on \(\mathrm{Cr}^{4+}\) is +4, and the charge on \(\mathrm{Br}^{-}\) is -1.
   • To balance the charges, we need four \(\mathrm{Br}^{-}\) ions for every \(\mathrm{Cr}^{4+}\) ion.
   • Empirical formula: \(\mathrm{CrBr}_4\).

4. \(\mathrm{Cr}^{4+}\) and \(\mathrm{S}^{2-}\):

   • The charge on \(\mathrm{Cr}^{4+}\) is +4, and the charge on \(\mathrm{S}^{2-}\) is -2.
   • To balance the charges, we need two \(\mathrm{S}^{2-}\) ions for every \(\mathrm{Cr}^{4+}\) ion.
   • Empirical formula: \(\mathrm{CrS}_2\).

Final Answer