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3.4.1—Nucleophiles

Syllabus
First assessment 2025
Objective
3.4.1
Level
SL

Recognizing Nucleophiles

A nucleophile is an electron-rich species that donates an electron pair to an electron-deficient centre.

both curved arrows begin at the nucleophile electron pair and end at E; Nu- gives a negatively charged adduct while neutral Nu gives a neutral adduct; the coordinate bond is shown as electron-pair donation from Nu to E.

Look for an available electron pair: OH⁻ and CN⁻ use a negative charge and lone pair, while NH₃ uses a lone pair without being an anion. A curly arrow must start at that pair and point toward the atom where the new bond forms.

Identifying Nucleophiles

[ 1 ]

Identify a nucleophile which could be used for this reaction.

Electron-Pair Sharing Summary

Retrieve the route: classify nucleophiles and electrophiles, show heterolysis, write substitution and addition mechanisms, map Lewis coordination, compare SN1/SN2, and restore aromaticity in benzene substitution.

Check electron-pair arrow origin and destination, leaving-group departure, intermediate identity, carbocation stability and the assessed mechanism boundary.