Question

What is pauli exclusion principle with examples?

Answer 1

Pauli Exclusion Principle.

The Pauli Exclusion Principle states that, in an atom or molecule, no two electrons can have the same four electronic quantum numbers.

As an orbital can contain a maximum of only two electrons, the two electrons must have opposing spins.

Answer 2

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

Explanation:

In Pauli's exclusion principle, no two electrons can occupy the same orbital and two electrons in the same orbital must have anti-parallel or opposite spin.

Example:

• A neutral helium atom has two bound electrons, and they occupy the lowest-energy ($1s$) states by attaining the opposite spin.
• Since spin is is a part of the electron's quantum state, the two electrons are in different quantum states and do not interrupt Pauli's exclusion principle.
• Though, there are only two different spin values for a given energy state.
• So, this property mandates that a lithium atom, which has $3$ bound electrons, cannot have its $3^{rd}$ electron exist in the $1s$ state.
• Meanwhile, it must subjugate one of the higher-energy $2s$ states instead.