Pauli's exclusion Principle is based on the arrangement of electrons in an atom.
According to Pauli's exclusion principle, no two atoms have the same set of quantum numbers.
Each atom containing an electron will have different sets of quantum numbers.
The electron should have different sets of (n, l, m, s) arrangements in which “n” denotes the Principle quantum numbers, “l” denotes the Angular momentum quantum number, “m” magnetic quantum number, “s” is the spin quantum number.
The principle is also applicable to the arrangement of spin in an atom, i.e. no two spins are arranged in the same direction.
If one spin is facing in the upward direction then the other will have to face in the downward direction.
Example: Oxygen has an electronic configuration equal to .