Question

WHAT DO U MEAN BY PAULI EXCLUSION PRINCIPLE.???

Answer 1

It states that no two electrons in an atom can have same set of four quantum number...
It means that in a shell 2 electrons cannot have same quantum number...It also states that electrons in a shell should spin opposite direction...

Answer 2

HEY HERE'S THE ANSWER.

Pauli formulated the exclusion principle which states that NO TWO ELECTRONS IN AN ATOM CAN HAVE THE SAME SET OF VALUES OF ALL FOUR QUANTUM NUMBERS.It means that each electron must have unique values for the four quantum numbers.
HOPE THIS'LL HELP YOU..!