Electronic Effects – Inductive, Mesomeric, Hyperconjugation and Reactive Intermediates
ChemistryOrganic ChemistryAges 17–18
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Organic Chemistry
2D explorer: attach –CH₃, –Cl, –NO₂, –OH or –OCH₃ to a saturated chain, a C=C chain or a benzene ring and see the inductive effect (+I, −I) along σ bonds, the mesomeric effect with curly arrows and contributing structures, and hyperconjugation of C–H bonds. Break bonds homolytically or heterolytically into free radicals or ions, sort electrophiles and nucleophiles, and compare the stability of carbocations, free radicals and carbanions from methyl to tertiary.
Lesson: Electronic effects, reagents and reactive intermediates
What it shows
Organic reactions are easier to predict once you know where the electrons are. This simulation shows the three electronic effects of substituents side by side: the inductive effect along σ bonds, the mesomeric (resonance) effect drawn with curly arrows and contributing structures, and hyperconjugation of C–H bonds. It then follows bonds as they break homolytically into free radicals or heterolytically into ions, asks you to sort electrophiles and nucleophiles, and compares the stability of carbocations, free radicals and carbanions using real bond-enthalpy and hydride-affinity data. Structures are drawn flat and simplified.
How to use
On Substituent effects, choose a Substituent, what it is Attached to and an Effect; for mesomeric effects and hyperconjugation press Next ▶ to step through the structures to the resonance hybrid. On Bond fission, choose a Bond and the Fission, then press Break bond. On Electrophiles and nucleophiles, drag each species into a box and check. On Stability of intermediates, choose an Intermediate and a Carbon, then press Record.
Parameters you can change
- Screen Substituent effects, Bond fission, Electrophiles and nucleophiles, Stability of intermediates
- Substituent –H (reference), –CH₃ (methyl), –Cl (chloro), –NO₂ (nitro), –OH (hydroxy), –OCH₃ (methoxy)
- Attached to Saturated chain –CH₂CH₂CH₃, C=C chain –CH=CH₂, Benzene ring –C₆H₅
- Effect Inductive, Mesomeric (resonance), Hyperconjugation
- Bond Cl–Cl (chlorine), H–Br (hydrogen bromide), (CH₃)₃C–Br (2-bromo-2-methylpropane), H₃C–Li (methyllithium)
- Fission Homolytic, Heterolytic: pair to left atom, Heterolytic: pair to right atom
- Intermediate Carbocation, Free radical, Carbanion
- Carbon Methyl, Primary (1°), Secondary (2°), Tertiary (3°)
Questions to explore
- Why does –OH withdraw electrons along a saturated chain but donate electrons to a benzene ring?
- Which fission of the (CH₃)₃C–Br bond gives a carbocation, and why is that direction favored?
- Why is the stability order of carbanions the reverse of that of carbocations?
