Number of electrons in the penultimate shell of $d-$block elements.

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

Explain on what factors the ionization enthalpies of elements having $d^{n}$ configuration depend upon? Explain the variation in ionization enthalpies of transition elements in the $3d$ series.

Select the correct order of ionic radii for the given ions:

Which of the following has a colored aqueous solution?

Which one of the following statements is true for transition elements?