Nucleophile is defined as

Nucleophile is defined as

• A. Electron pair acceptors
• B. Electron pair donors
• C. A species that donates a proton
• D. Electron pair donor

Answer: (D)

Nucleophiles are species that donate an electron pair to an electron-poor center. In Lewis terms, a nucleophile is a Lewis base because it provides a pair of electrons to form a bond with an electrophile. This is why the defining description is an electron pair donor. Donating a proton describes acid behavior, not nucleophilicity, and an electron pair acceptor would be an electrophile, not a nucleophile. Saying it is an electron pair donor (the standard way to state the definition) captures the essential idea that nucleophiles supply electrons to form new bonds.

Nucleophiles are species that donate an electron pair to an electron-poor center. In Lewis terms, a nucleophile is a Lewis base because it provides a pair of electrons to form a bond with an electrophile. This is why the defining description is an electron pair donor. Donating a proton describes acid behavior, not nucleophilicity, and an electron pair acceptor would be an electrophile, not a nucleophile. Saying it is an electron pair donor (the standard way to state the definition) captures the essential idea that nucleophiles supply electrons to form new bonds.