Q.State and explain Pauli's Exclusion Principle.

Pauli's Exclusion Principle states that no two electrons in an atom can have the same set of all four quantum numbers.

Wolfgang Pauli's Exclusion Principle states: "No two electrons in an atom can have the same values for all four quantum numbers (n, l, ml, ms)."

Every electron in an atom is described by a unique set of four quantum numbers — principal (n), azimuthal (l), magnetic (ml), and spin (ms). Since a given orbital is fully specified by fixed n, l, and ml values, at most two electrons can occupy that orbital, and for those two electrons to have different quantum-number sets, they must differ in their spin quantum number — one +1/2 (spin up) and one −1/2 (spin do …