Chapter 5, Problem 76A

Interpretation Introduction

Interpretation:

The sequence in which electrons fill the atomic orbitals related to a sublevel needs to be explained.

Concept introduction:

The filling of electrons starts from the lowest available energy level to higher energy level.

Answer to Problem 76A

All orbitals of a subshell first singly filled before pairing of electrons

Explanation of Solution

While filling orbitals following rules must be followed:

• Aufbau Principle states that in the ground state electrons of an atom fill the orbital with lowest energy first and upcoming electrons are filled in the order of increasing their energies.
• Hund's rule states that pairing of electrons do not occurs until each and every orbital in a subshell is singly filled with electrons having same spin.
• Pauli Exclusion Principle states that in an atom no two electrons present in a same orbital having same spin.

Conclusion

All orbitals of a subshell first singly filled before pairing of electrons.