Question

Four successive members of the first row transition elements are listed below with atomic numbers. Which one of them is expected to have the highest $E_{M^{3+}/M^{2+}}^0$ value?

• A. Cr(Z = 24)
• B. Mn (Z = 25)
• C. Fe (Z = 26)
• D. Co (Z = 27)

Answer 1

The correct option is D Co (Z = 27)

You would expect $M{n}^{2+}$ to be the most stable but $C{o}^{2+}$ is the most stable! Remember that this data is experimental.