A chemist lectures about this definition for acids and bases. The acid-base behavior is analyzed in terms of how electrons are transferred between compounds rather than in terms of how hydrogen ions are transferred. What is the chemist defining?

The Lewis concept defines acid–base behavior in terms of electron pairs: a Lewis acid accepts an electron pair, and a Lewis base donates one. This differs from the Brønsted–Lowry concept, which focuses on the transfer of hydrogen ions (protons). Therefore, the chemist is describing the Lewis concept of acids and bases.

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