An ion with a charge of $-2$ has the electronic configuration $1s^2, 2s^2, 2p^6$. Identify the ion.

What is the atomic number of the element with $M^{2+}$ ion having electronic configuration $[Ar] 3d^8$?

The angular momentum of an electron in a $d$ orbital is equal to:

The maximum number of orbitals present in $n=4$ energy level of an atom and the maximum number of electrons with spin value $+\frac{1}{2}$ in the same orbitals are, respectively.

The number of radial nodes in a $2s$ orbital is equal to that in a ........ orbital.

Which of the following sets of quantum numbers is possible?