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Example Questions
Example Question #11 : Identifying Aromatic Compounds
Assuming that this molecule is planar, determine whether this molecule is aromatic, and name the number of electrons ( molecular orbitals).
Aromatic, 6 electrons
Not aromatic, 8 electrons
Aromatic, 8 electrons
Non aromatic, 6 electrons
Not aromatic, 8 electrons
There is no p orbital surrounding the Boron atom, so the ring does not have a fully conjugated pi system. In addition, there are 8 electrons, which does not follow Huckel's rule (an aromatic system contains 4n+2 electrons). The pi electrons include the lone pair (not shown, but implicit) on the nitrogen atom, which is why the answers with "6 electrons" are not correct.
Example Question #11 : Organic Functional Groups And Molecules
Assuming that this molecule is planar, determine whether this molecule is aromatic, and name the number of electrons (not molecular orbitals).
Not aromatic, 6 electrons.
Aromatic, 6 electrons.
Not aromatic, 8 electrons.
Aromatic, 8 electrons.
Aromatic, 6 electrons.
The lone pairs on the two nitrogen atoms reside in sp2 orbitals, meaning they do not participate in resonance. Within the ring, there are three bonds, meaning there are six electrons. Thus, the molecule is aromatic because it is planar and follows Huckel's rule.
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