Molecules with an extended π system well described by resonance hybrid

In summary, molecules with an extended π system, such as linear polyenes and polyaromatic compounds, exhibit resonance and delocalization of electrons in molecular orbital theory. This can be seen in the structure of these compounds, as the double bonds are shared among multiple rings, resulting in an extended π system.
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Huzaifa
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Homework Statement:: [...] Molecules with an extended π system such as linear polyenes and polyaromatic compounds are well described by resonance hybrids as well as by delocalized orbitals in molecular orbital theory.
Relevant Equations:: N/A

This is not a Homework question. I was reading Resonance (chemistry) from Wikipedia. I am not able to understand this sentence, "Molecules with an extended π system such as linear polyenes and polyaromatic compounds are well described by resonance hybrids as well as by delocalized orbitals in molecular orbital theory "

What is an extended π system? Given examples of linear polyenes and polyaromatic compounds of extended π system, when I searched polyaromatic, I found bee honeycomb images.
Hexabenzocoronene.svg.png


[Moderator's note: moved from a homework forum.]
 
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You see a honeycomb, I see a system where each individual ring - thanks to the resonance - has a π system. They do combine meaning the system is extended.

For some rings it is immediately obvious, for some it requires spotting that - while the double bond is drawn as if it was on the other side - it is technically shared by two rings, for some it requires drawing a resonance structure. But it is all there.
 
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1. What is a molecule with an extended π system?

A molecule with an extended π system is one that has a large number of delocalized π electrons, typically in a conjugated system. This allows for the formation of multiple resonance structures, resulting in increased stability and unique chemical properties.

2. How is a molecule's π system described by resonance hybrid?

A molecule's π system is described by resonance hybrid when it exists as a combination of two or more resonance structures. This is due to the delocalization of π electrons, which allows for the movement of electrons between different atoms or bonds within the molecule.

3. What factors contribute to the stability of molecules with an extended π system?

Molecules with an extended π system are more stable due to the delocalization of π electrons, which leads to a lower overall energy state. Additionally, the presence of multiple resonance structures allows for the distribution of charge, reducing the likelihood of a single, unstable structure.

4. Can molecules with an extended π system exhibit unique chemical properties?

Yes, molecules with an extended π system can exhibit unique chemical properties due to their increased stability and delocalized electrons. This can result in enhanced reactivity, increased conjugation, and altered electronic and optical properties.

5. How does the concept of resonance hybridization impact the understanding of molecular structure?

The concept of resonance hybridization is important in understanding molecular structure because it explains the delocalization of π electrons and the formation of multiple resonance structures. This allows for a more accurate depiction of the true structure of a molecule, rather than a single, static structure.

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