Chapter 18.9, Problem 18.12CP

Interpretation Introduction

Interpretation:

A molecular orbital energy level diagram for ${\text{O}}_{\text{2}}^{\text{-}}$ has to be drawn with MOs derived from Oxygen 2s and 2p orbitals.  Also the electron population of MOs is to be shown and paramagnetic nature of ${\text{O}}_{\text{2}}^{\text{-}}$ has to be verified.

Concept Introduction:

Molecular orbital theory:

Molecular orbital theory states that atomic orbitals lose their individuality and electrons of the molecule present in the new orbital called molecular orbital. A brief outline of this theory is given below.

• Atomic orbital of equal energy combine together to form molecular orbital.
• Shape of molecular orbital depending on the shapes of combining atomic orbital.
• Bonding orbitals denoted by $\text{σ}$, $\text{π and δ}$ and antibonding orbital are denoted by ${\text{σ}}^{\ast }$, ${\text{π}}^{\ast }{\text{ and δ}}^{\ast }$.
• Molecular orbital are filled in increasing order of their energies, starting with orbital of least energy.  This is called Aufbau principle.
• A molecular orbital is filled with only two electrons with opposite spins.  This is called Paul’s exclusion principle.

Paramagnetic and diamagnetic nature:

If all electrons in the molecule are paired, the substance is diamagnetic nature and substance has unpaired electron(s) are called paramagnetic nature.