The $3d$ elements show variable oxidation states because the energies of the following sets of orbitals are almost similar:

Write a brief note on the electronic configurations of the transition elements.

Magnetic moment of $Gd^{3+}$ ion $(Z = 64)$ is .......... $B.M.$

Consider $n$ as the number of lone pairs of electrons present in the equatorial position of the most stable structure of $ClF_3$. The ions from the following with $n$ number of unpaired electrons are :
$A. V^{3+}$
$B. Ti^{3+}$
$C. Cu^{2+}$
$D. Ni^{2+}$
$E. Ti^{2+}$
Choose the correct answer from the options given below :

Which pair of elements from the following has half-filled $d$-orbitals in their observed electronic configuration?

Which of the elements possess only one electron in the $5d$-orbital?