Chapter 7, Problem 7.88QP

Interpretation Introduction

Interpretation: The delocalized molecular orbital differ from localized molecular orbital such that in ${\text{H}}_{\text{2}}$ and ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}$ has to be explained.  In addition, the minimum condition for forming a delocalized molecular orbital has to be explained.

Concept Introduction: Molecular orbitals are formed by the combination of the atomic orbitals of the atoms in the molecule.  The properties of the newly formed molecular orbital will be different from their individual atomic orbitals. In molecular orbital theory, electrons shared by atoms in a molecule reside in the molecular orbitals.

In localized molecular orbital, molecular orbitals are considered to be localized between the individual bonds.

Delocalized molecular orbitals are extended over two or more atoms, these are not confined to adjacent bonding atoms.  Therefore, the electrons are free to move around the entire molecule.