Question

How is the Pauli Exclusion Principle important in regards to the “octet rule”?

Answer 1

Hint: Pauli’s exclusion principle helps us to understand the electron arrangements in atoms and molecules and it also gives an explanation for the classification of elements in the periodic table.

Complete Step By Step Answer:
Pauli exclusion principle essentially states that in a single atom no two electrons will have an identical set or the same quantum numbers ( $ n,l,{m_l} $ , and $ {m_s} $ )
Pauli's exclusion principle is in fact the main reason why we have the idea of an 'octet rule" and why some transition metals like chromium have access to $ 12 $ bonding electrons, and sometimes up to even $ 18 $ bonding electrons.
The Pauli Exclusion Principle is based on two main principles:
Only two electrons can be in the same orbital at the same time.
The spins of the two electrons in the same orbital must be opposing or the orbital must be antiparallel.
A vast range of physical phenomena can be explained using the Pauli exclusion principle.
It aids in the description of the various chemical elements and their roles in the formation of chemical bonds.
This method can also be used to define the periodic table.
The concept is also a fundamental principle of quantum mechanics, which is mostly studied in physics.
It is also useful in astrophysics.

Note:
The quantum number $ n $ is the most important. It refers to the electron's position in the innermost shell. The orbital angular momentum quantum number, $ l $ aids in the determination of an orbital shape. The number of orbitals and their orientation are revealed by the magnetic quantum number, $ {m_l} $ .The spin quantum number, $ {m_s} $ , determines the electron's spin direction.