Question

Discuss the significance of the Pauli Principle, Hund’s rule and the Aufbau principle in obtaining the ground state configurations of multi-electron atoms.

Answer 1

Pauli principle: It says that no two electron of an atom can have same four quantum number. This principle describes the way atoms share electrons , variety of chemical elements and

chemical combination.

Hund's rule : Every orbital in a sublevel is singly occupied untill

any orbital is doubly filled.

This rule explains how electrons are arranged in degenerate orbitals.

1. Pe Py Pa Right wrong

Aufbau principle: It says that lower energy atomic orbitals are filled first. Order of increasing energy of atomic orbitals increases as sum of n and l value. When n+l is same , lower the value n , lower will be the energy of the atomic orbital.

Increasing order of atomic orbital is

1s< 2s< 2p< 3s< 3p < 3d < 4s ...

Using aufbau principle the orbitals for electrons in a multi-electron system can be determined.