Abstract In organic chemistry teaching, the delocalization of π orbitals are described by both the molecular orbital (MO) theory and the resonance structures of the valence bond (VB) theory. On the other hand, hyperconjugation effects of σ bond are mainly described by MO theory, and it usually does not have the corresponding resonance VB description. This paper tries to describe the hyperconjugation effects of σ bond by resonance structures. The resulting representations are clear and easy to understand. Moreover, knowledge points from different chapters can be linked together. It will help students master organic chemistry knowledge and gain a deeper understanding of the electronic structure and resonance theory.
