AP | A-Level | IB | NCERT 11 + 12 – FREE NOTES, RESOURCES AND VIDEOS!
S1.1 - Introduction to the particulate nature of matter S1.2 - The nuclear atom S1.3 - Electron configurations S1.4 - Counting particles by mass - The mole S1.5 - Ideal gases S2.1 - The ionic model S2.2 - The covalent model S2.3 - The metallic model S2.4 - From models to materials S3.1 - The periodic table - Classification of elements S3.2 - Functional groups - Classification of organic compounds R1.1 - Measuring enthalpy changes R1.2 - Energy cycles in reactions R1.3 - Energy from fuels R1.4 - Entropy and spontaneity AHL R2.1 - How much? The amount of chemical change R2.2 - How fast? The rate of chemical change R2.3 - How far? The extent of chemical change R3.1 - Proton transfer reactions R3.2 - Electron transfer reactions R3.3 - Electron sharing reactions R3.4 - Electron-pair sharing reactions

R3.4 - Electron-pair sharing reactions

3.4.1 Nucleophilic 3.4.2 Nucleophilic Substitution Reaction 3.4.3 Electrolytic Fission and Ionic Formation 3.4.4 Electrophilic 3.4.5 Electrophilic Addition to Alkenes 3.4.6 Lewis Acids and Bases (AHL) 3.4.7 Lewis Acid-Base Reaction and Co-ordinate Bonds (AHL) 3.4.8 Complex Ions and Ligand Co-coordination (AHL) 3.4.9 SN1 and SN2 Reaction (AHL) 3.4.10 Leaving Group and Substitution (AHL) 3.4.11 Electrophilic Addition of Alkenes (AHL) 3.4.12 Major Product of Addition Reaction (AHL) 3.4.13 Electrophilic Substitution of Benzene (AHL)

Nucleophiles and Their Role in Reactions

Specification Reference R3.4.1

Quick Notes:

  • A nucleophile is a species that donates a pair of electrons to form a new covalent bond.
  • It attacks an electrophile (electron-deficient species).
  • Can be negatively charged or neutral.
  • Common nucleophiles include:
    • OH, CN, NH3, H2O, Cl
  • Nucleophiles are electron-rich and attracted to electron-poor centres.

Full Notes:

What is a Nucleophile?

A nucleophile is an electron pair donor.

In reactions, a nucleophile donates a lone pair of electrons to its reaction partner (an electrophile) forming a covalent bond.

Characteristics of Nucleophiles

Nucleophiles must have a lone pair of electrons.

They can be negatively charged ions (e.g. OH, CN, Cl) or neutral molecules (e.g. H2O and NH3).

They are attracted to δ+ (partially positive) or electron-deficient atoms in other molecules.

Common Nucleophiles

Nucleophile Formula Charge Notes
Hydroxide OH Negative Strong nucleophile (common in substitution)
Cyanide CN Negative Attacks carbon atoms; extends carbon chains
Ammonia NH3 Neutral Lone pair on nitrogen donates electrons
Water H2O Neutral Weak nucleophile
Chloride Cl Negative Weak nucleophile compared to OH⁻

Summary