Topic 18: Acids and bases - 18.1 Lewis acids and bases

Nature of science:

Theories can be supported, falsified or replaced by new theories - acid–base theories can be extended to a wider field of applications by considering lone pairs of electrons. Lewis theory doesn't falsify Brønsted–Lowry but extends it. 2.5


Essential idea: The acid-base concept can be extended to reactions that do not involve proton transfer.

A Lewis acid is a lone pair acceptor and a Lewis base is a lone pair donor.

When a Lewis base reacts with a Lewis acid a coordinate bond is formed.

A nucleophile is a Lewis base and an electrophile is a Lewis acid.

Applications and skills

Application of Lewis' acid-base theory to inorganic and organic chemistry to identify the role of the reacting species.


Both organic and inorganic examples should be studied.

Relations between Brønsted-Lowry and Lewis acids and bases should be discussed.