For an atom with atomic number $Z = 25$,determine the total number of $s$ electrons present.

If three electrons could be accommodated in an orbital,then the element with atomic number $50$ will belong to:-

$A$: No two electrons in an atom can have the same set of all four quantum numbers.
$R$: Two electrons in an atom can exist in the same shell,subshell,or orbital only if they have opposite spins.

For how many electrons in an atom is $n = 3, m_l = 1$ possible?

Consider the hypothetical situation where the azimuthal quantum number,$l$,takes values $0, 1, 2, \ldots, n+1$,where $n$ is the principal quantum number. Then,the element with atomic number

For an electron in a $4d$ orbital,which of the following sets of quantum numbers is not possible?