Lewis concept of acids and bases
Definitions based on electron pair donation and acceptance, where Lewis acids accept electron pairs and Lewis bases donate electron pairs.
What is Lewis concept of acids and bases?
A chemical species that can accept an electron pair to form a coordinate covalent bond.
Key points
- Define Lewis acid and Lewis base.
- Identify Lewis acids and Lewis bases in given chemical species.
- Explain the formation of coordinate covalent bonds in Lewis acid-base reactions.
- Differentiate the Lewis concept from Brønsted-Lowry and Arrhenius concepts.
Common exam trap
Confusing Lewis acids/bases with Brønsted-Lowry acids/bases.
Definitions
- Term
Lewis Acid
- Meaning
A chemical species that can accept an electron pair to form a coordinate covalent bond.
- Term
Lewis Base
- Meaning
A chemical species that can donate an electron pair to form a coordinate covalent bond.
- Term
Coordinate Covalent Bond
- Meaning
A type of covalent bond in which one atom contributes both electrons to the shared pair.
- Term
Adduct
- Meaning
A product formed by the direct combination of two or more separate molecules, often involving a Lewis acid-base reaction.
Learning objectives
Define Lewis acid and Lewis base.
Identify Lewis acids and Lewis bases in given chemical species.
Explain the formation of coordinate covalent bonds in Lewis acid-base reactions.
Differentiate the Lewis concept from Brønsted-Lowry and Arrhenius concepts.
Apply the Lewis concept to predict reaction products in certain cases.
Prerequisites
Understanding of chemical bonding (covalent, coordinate covalent).
Knowledge of electron pairs (lone pairs, bonding pairs).
Basic understanding of atomic structure and octet rule.
Familiarity with Brønsted-Lowry and Arrhenius concepts of acids and bases.
Common mistakes
Confusing Lewis acids/bases with Brønsted-Lowry acids/bases.
Not identifying species with incomplete octets as potential Lewis acids.
Overlooking species with lone pairs as Lewis bases.
Assuming all metal ions are Lewis acids without considering their charge and coordination environment.
Keywords
Lewis acid
Lewis base
Electron pair acceptor
Electron pair donor
Coordinate covalent bond
Adduct
Lewis theory
Acid-base concepts
Practice preview
In the reaction: BCl₃ + Cl⁻ → [BCl₄]⁻, which species acts as a Lewis acid?…
easy
Consider the reaction between BF₃ and NH₃. Which statement is correct regarding this reaction according to the Lewis concept?…
medium
According to the Lewis concept of acids and bases, which of the following is a Lewis acid?…
easy