The electronic configuration of calcium ion $(Ca^{2+})$ is

The quantum number which explains the line spectra observed as doublets in the case of hydrogen and alkali metals, and doublets and triplets in the case of alkaline earth metals is:

Which of the following arrangements shows the correct order of decreasing paramagnetism?

Which set of quantum numbers for an electron of an atom is not possible?

For a magnetic quantum number $m = 0, \pm 1$,the value of the principal orbital (azimuthal quantum number $l$) corresponds to which subshell,and what is the minimum principal quantum number $n$ required for this set?

Following Hund's rule,which element contains six unpaired electrons?