Which of the following elements has the maximum first ionization potential?

The correct order of $E^o$ $M^{2+}/M$ values with negative sign for the four successive elements $Cr$,$Mn$,$Fe$ and $Co$ is

Why are the $E^{\circ}$ values for $Mn^{2+}$,$Ni^{2+}$,and $Zn^{2+}$ more negative than expected?

Four successive members of the first series of the transition metals are listed below. For which one of them is the standard electrode potential $(E^o_{M^{2+}/M})$ value positive?

The electronic configuration $4d^3$ $5s^2$ belongs to which group in the periodic table?

The lanthanide contraction is responsible for the fact that