Quantum numbers are assigned to get complete information of electrons regarding their energy. angular momentum. spectral lines etc. Four quantum numbers are principal quantum numbers which tell the distance of electron from nucleus. energy of electron in a particular shell and its angular momentum. Azimuthal quantum number tells about the subshells in a given shell and of course shape oi orbital. Magnetic quantum number is the study of orientations or degeneracy of a subshell. Spin quantum number which defines  the spin of electron designated as $+\frac{1}{2}\text{ or }-\frac{1}{2}$ represented by respectively Electrons are filled in orbitals following Aufbau rule. Pauli's exclusion principal and Hund's rule of maximum multiplicity. On the basis of this  answer the following questions.