Question

Write the significance of $4$ quantum numbers

Answer 1

The set of four quantum numbers help us to get complete information about all electrons in an atom that is, energy shell, type of orbital occupied and the orientation of that orbitals.

Complete step by step answer:
The principal quantum number ‘n’ designates the principal electron shell because ‘n’ describes the most probable distance of the electrons from the nucleus. The larger the number n is, the farther the electron is from the nucleus and the larger the size of the orbit, the large is the atom.
Azimuthal quantum number $\left( l \right)$: It has values from $0$ to $n - 1$ there are $'n'$ sub shell in the ${n^{th}}$ shell, $'l'$ identifies the subshell and determines the shape of orbital and the value of $'l'$ is the designated by the letters $s,p,d,f$ which corresponds to value $0,1,2,3.....$ respectively. The number of angular nodes is equal to the value of the angular quantum number $\left( l \right)$.
Magnetic quantum number $\left( {{m_l}} \right)$ determines the number of orbitals and their orientation within a subshell unlike $n,$ $l$ and ${m_l}$.
The electron spin quantum number $\left( {{m_s}} \right)$ does not depend upon another quantum number. It designates the direction of the electron spin and may have spin of $+ \dfrac{1}{2}$ and $- \dfrac{1}{2}$. Only two electrons can occupy a single orbital with opposite spins.

Note: Atomic orbitals can be specified by giving their corresponding energies and angular momenta which are quantised (i.e. they can have some specific values). The quantised values can be expressed in terms of quantum number. They are used to get complete information about electrons.