Which species is represented by the following distribution of π electrons in the molecular orbitals and energy levels diagram?
A)I
B)II
C)III
D)IV

Question

Which species is represented by the following distribution of π electrons in the molecular orbitals and energy levels diagram? 
A)I 
B)II 
C)III 
D)IV

Quizplus · Accepted Answer

The diagram shows 6 π electrons distributed in three molecular orbitals. This is the characteristic distribution for a species with a planar, cyclic structure and a conjugated π system. Only option III satisfies these criteria. Option I has 8 π electrons and is therefore not conjugated, and options II, IV, and V have non-planar structures that do not allow for conjugation.

Which Species Is Represented by the Following Distribution of π