The usual statement of the Pauli Exclusion Principle is that no two electrons in an atom can have the same set of four quantum numbers n, l. It is not relevant for particles with an integer spin such as bosons which have symmetric wave functions. One explanation as to why the differences between the term symbols that arise from a p2 p 2 configuration relative to a pp configuration is the Pauli Exclusion principle. It is applicable to other particles applies to other particles of half-integer spin such as fermions. However, Pauli Exclusion Principle is not applicable to electrons. If the state has one electron, then it can either be spin-up or spin down. In simple words, Paulis exclusion principle states that in the same orbital, there will be no more than two electrons and the two electrons contain opposite. By state here we mean a set of properties. The Pauli Exclusion Principle is defined as a rule that states that no two electrons can share the same four quantum numbers within the same atom or molecule. It usually moves to the lowest energy state or it shifts to the outermost shell. No two electrons in an atom can have identical quantum numbers. (actually, protons and neutrons obey the same principle, while photons do not). The principle therefore is very effective with respect to atoms when we look at the atoms whenever it gains a new electron or electrons, The atom that is involved in donating the electron in a shell is also predicted by the Pauli’s Exclusion principle. The electronic configuration of cations is assigned by removing electrons first in the outermost p orbital, followed by the s orbital and finally the d orbitals (if any more electrons need to be removed). In chemistry, the electron shell structure of atoms is determined by the Pauli’s exclusion principle. That is, we follow the three important rules: Aufbau Principle, Pauli-exclusion Principle, and Hund's Rule. In the year 1945,Wolfgang Pauli was also awarded the Nobel prize for his discovery of Pauli exclusion principle, and for his overall contribution in the field of quantum mechanics Pauli Exclusion Principle in Chemistry

In simple terms, the Pauli exculsion principle paired electrons to have opposite spins. This means an orbital can hold a maximum of two electrons, and then the electrons must have opposite spins, +1/2 and -1/2. On the other hand, the principle describes the elementary particles such as quarks, electrons, neutrinos, and baryons, these form the elementary particles of the fermion No two electrons in a atom can have an identical set of four quantum numbers. The Pauli exclusion principle stipulates that no two particles of half-integer spin (fermions) can occupy the same quantum state. In the year 1940 the Pauli’s Exclusion principle expands, to cover the fermions under spin-statistics theorem.

The principle basically describes the behaviour of electrons, The principle formulated by an Austrian physicist named Wolfgang in the year 1925.

Pauli exclusion principle simplified