Which element from the following does $NOT$ exhibit a magnetic moment in the $+2$ oxidation state?

Determine whether the following statements are True $(T)$ or False $(F)$:
$(a)$ The atomic radii of the elements of the second transition series $(4d)$ are larger than those of the first transition series $(3d)$.
$(b)$ $Cr^{+}$,$Mn^{2+}$,and $Fe^{3+}$ have the same electronic configuration.
$(c)$ $Cr^{+}$,$Mn^{2+}$,and $Fe^{3+}$ have the same $d^5$ electronic configuration.

Find the value of spin-only magnetic moment for chromium cation in $+2$ state. (in $BM$)

Which of the following is a correct statement?

The number of $4f$ electrons in the ground state electronic configuration of $Gd^{2+}$ is ........ .
[Atomic number of $Gd=64$]

Which of the following graphs is the correct representation of the relationship between atomic number $(Z)$ and the magnetic moment of $d-$block elements? [Outer electronic configuration : $(n - 1)d^x\ ns^{1\ or\ 2}$]