Question

While writing the following electronics configuration of $Fe$ atom in the ground state some rules have been violated.

Which of the following has/have been violated?

I. Aufbau's rule
II. Hund's rule
III. Pauli's exclusion priciple

• A. $I,II$
• B. $III$ only
• C. $I,III$
• D. $I,II,III$

Answer 1

The correct option is C $I,III$

The Aufbau principle states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. In this way, the electrons of an atom or ion form the most stable electron configuration possible.

The Pauli exclusion principle is the quantum mechanical principle which states that two or more identical fermions (particles with half-integer spin) cannot occupy the same quantum state within a quantum system simultaneously.

But in 3d subshell orbital is not fiied and 4s subshell is full filled, so Afbau principle is voilated

and in 3d subshell in first orbital two electrons have same spin quantum number , so Pauli exclusion princip,e is voilated