Question

Why two electrons in atom can have the same set quantum number?

Answer 1

Explanation:

Pauli Exclusion Principle

An electron, being a fermion, obeys this principle, so no two electrons in the same atom can have the same quantum numbers. Each orbital has space for 2 electrons, with ms values with opposite sign. These electrons are considered spin-paired.

Answer 2

Answer:

So the two electrons in the 1s orbital are each unique and distinct from one another because their spins are different. This observation leads to the Pauli exclusion principle, which states that no two electrons in an atom can have the same set of four quantum numbers.

Explanation:

hope that helps you