Conjugated dienes are more stable than non conjugated dienes (both isolated and cumulated) due to factors such as delocalization of charge through resonance and hybridization energy. This can also explain why allylic radicals are much more stable than secondary or even tertiary.

Introduction:
Conjugated alkenes refer to a class of organic compounds that contain two or more carbon-carbon double bonds with alternating single bonds. They are known to be more stable compared to isolated and cumulated alkenes. This stability can be attributed to various factors, including resonance, hyperconjugation, and bond length considerations.

Resonance:
One of the key factors contributing to the stability of conjugated alkenes is resonance. In a conjugated system, the p-orbitals of the double bonds can overlap, creating a delocalized pi system. This delocalization allows for the distribution of electron density throughout the molecule, resulting in a lower energy state. The presence of resonance forms leads to stabilization and increased stability.

Hyperconjugation:
Hyperconjugation is another factor that contributes to the stability of conjugated alkenes. It occurs when the electrons in a sigma bond interact with an adjacent pi system, resulting in electron delocalization. In conjugated alkenes, hyperconjugation allows for the interaction between the sigma bonds of the single bonds adjacent to the double bonds and the pi system. This interaction stabilizes the molecule by distributing electron density, reducing electron-electron repulsion, and lowering the overall energy.

Bond Length Considerations:
In isolated alkenes, the carbon-carbon double bond is shorter and stronger compared to the single bonds. However, in conjugated alkenes, the presence of alternating single bonds between the double bonds results in an intermediate bond length. This intermediate bond length is more favorable and energetically stable compared to both isolated and cumulated alkenes. The equalization of bond lengths helps to distribute electron density and reduces bond strain, enhancing the stability of the conjugated system.

Conclusion:
Conjugated alkenes are more stable than isolated and cumulated alkenes due to the presence of resonance, hyperconjugation, and the intermediate bond length. Resonance allows for the delocalization of electron density, while hyperconjugation facilitates electron distribution and reduces electron-electron repulsion. The intermediate bond length in conjugated alkenes helps to minimize bond strain and stabilize the molecule. These factors combined contribute to the overall stability of conjugated alkenes, making them more thermodynamically favorable compared to their isolated and cumulated counterparts.

In conjugated alkadiene resonance takes place