Which one of the following is an example of non-$typical$ transition elements?

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

The metal that has a very low melting point and whose periodic position is close to a metalloid is:

The $E^{\Theta} (M^{2+} / M)$ value for copper is positive $(+0.34 \ V)$. What is the possible reason for this? (Hint: consider its high $\Delta_{a} H^{\Theta}$ and low $\Delta_{hyd} H^{\Theta}$)

The number of unpaired electrons is maximum in (Atomic no. : $Ti = 22; V = 23; Cr = 24; Fe = 26$)

Which of the following statements is incorrect?