Atomic Structure Principle

Question 1

Pauli Exclusion Principle

Answer 1

In a given atom, no two electrons can have the same set of four quantum numbers (n, l, ml, ms)
Therefore, an orbital can hold only two electrons, and they must have opposite spins.

Question 2

Aufbau Principle

Answer 2

As protons are added one by one to the nucleus to build up the elements, electrons are similarly added to these hydrogen-like orbitals.

Question 3

Hund’s Rule

Answer 3

The lowest energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by the Pauli principle in a particular set of degenerate orbitals