There is an unknown container of metal(M) in the stockroom. To determine the metal’s identity, the following galvanic cell was constructed at 25°C:M(s) ǀ M2+(aq, 0.747 M) ‖ Au3+(0.0496 M) ǀ Au(s) If the measured cell potential is 4.388 V, what is the identity of the unknown metal? The metal is an alkaline earth metal, this information should help.

Half-Reaction E° (V)
Au3+ + 3e-→ Au +1.498
Be2+ + 2e-→ Be -1.847
Mg2+ + 2e-→ Mg -2.372
Ca2+ + 2e-→ Ca -2.868
Sr2+ + 2e-→ Sr -2.890
Ba2+ + 2e-→ Ba -2.912
Ra2+ + 2e-→ Ra -2.920