Indetify (+M) mesomeric &(-M) group of following

Identify (+M) mesomeric & (-M) group of following.

Mesomeric Effect

Mesomeric Effect (±M, ±R)

Indetify the group of plants possessing leaf tendrils

Identify which of the following group as +m as well as -m ?

In the electrophilic substituion of benzene ring, the second substituent is directed by the group already present. Electron releasing groups (+I and +M) are ortho-para-directing and activating, whreas the electron withdrawing groups (-I and -M) are meta-directing and deactivating. Halogens are placed under the category of +T (Tautomeric) groups because they have -Ibdyctuve abd +Mesomeric effect. These groups are deactivating but ortho-para-directing. In the introduction of third group to the benzene ring, the product of minimum steric gindrance is formed. Which of the following is not an ortho, para-directing group ?

Identification of +m & -m groups : If the first atom of the group has lone pair or negative charge shows +m effect. +m group increases electron density at ortho and para position of benzene ring. If the group has vacant p- orbital on first atom, also a multipal bonded group in which second atom is more electronegative than the first then it shows -m effect. -m group decreases electron density of ortho and para position of benzene ring. Identify which of following group/s show -m effect when attached with benzene ring.

Resonance |Mesomeric Effect| +M Group| -M Group - Electron Withdrawing Group|Summary

Mesomerism is extended resonance. Atoms or groups with lone pairs of electrons release electrons when connected to doubly bonded carbons. It is +M effect. Unsaturated groups when connected to doubly bonded carbons withdraw pi electrons from the doubly bonded carbons. It is -M effect. Here the double bond is the unsaturated group should be between less electronegative atom and more electronegative atom. Which of the following is most stable?