Maximum oxidation state is shown by

Although $Cr^{3+}$ and $Co^{2+}$ ions have the same number of unpaired electrons,the magnetic moment of $Cr^{3+}$ is $3.87 \ BM$ and that of $Co^{2+}$ is $4.87 \ BM$. Why?

Which element of the $3d$-series has the highest third ionisation enthalpy?

Which of the following general configurations of the outermost shell represents the chromium element [$Cr$'s atomic number $= 24$]?

The tendency towards complex formation is maximum in

The lanthanide contraction is responsible for the fact that