Comprehension # 1
Read the following rules and answer the questions at the end of it.
Electrons in various suborbits of an filled in increasing order to their energies.
Pairing of electrons in various orbitals of a suborbit takes places only after each orbital is half-filled.
No two electrons in an atom can have the same set of quantum number.
While writing the following electronic configuration of Fe some rules have been violated :
I : Aufbau's rule,
II : Hund's rule
III : Pauli's exclusion principle

Options

A. `I,II`
B. `II,III`
C. `I,III`
D. `I,II,III`

Answer

D

Explanation

`Fe=[Ar]3d^(6)4s^(2)`

Hund's and Pauli's principle is voileted.