Question

What is the connection between the Pauli Exclusion principle, the Aufbau principle, the indeterminacy of fermions, electron configurations and quantum numbers. Why is shielding more effective for electrons in orbitals with lower principal quantum number than for electrons within the same shell?

Answer 1

All the mentioned topics like the Pauli Exclusion principle, the Aufbau principle, the indeterminacy of fermions, and quantum numbers will describes electron configuration and its quantum mechanics

To write the electron configuration for a particular atom we must follow the Aufbau principle, Pauli Exclusion principle.

the Aufbau principle says that electrons will fill lowest energy orbitals before filling the highest energy orbitals in an atom.example electrons will fill 1s orbital before 2s orbitals

Pauli Exclusion principle will says that no two electrons in an orbital will have same set of quantum numbers, i.e spin quantum numbers +1/2 and -1/2, that's the reason why we will write the electrins in an orbital with opposite spin.

the indeterminacy of fermions will says that you will never simultaneously known the exact speed and position of the object.this principle will helps to develop quantum mechanics.quantum numbers will describes the electron position in an atom.

Shielding more effective for electrons in orbitals with lower principal quantum number than for electrons within the same shell because

The orbital with lower principal quantum number will be more close to the nuclei hence these will show more shielding effect

within a shell the shielding effect will be S>P>D>F, because of more penetration power