What is the number of protons in the nucleus of an element that has the maximum number of unpaired electrons in the $2p$ subshell?

The magnetic quantum number for the valence electron of a sodium atom is:

Aqueous solution of which salt will not contain ions with the electronic configuration $1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6$?

The number of electrons that can be accommodated in $d_{z^2}$ orbital is

When the value of the principal quantum number $n$ is $3$,what are the permitted values of the azimuthal quantum numbers $l$ and the corresponding magnetic quantum numbers $m$?

The element with the electronic configuration $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^1$ is