Valence Bond Theory (VBT)
Explains bond formation through orbital overlap, types of bonds (σ, π), and hybridization.
What is Valence Bond Theory (VBT)?
The phenomenon where atomic orbitals of two atoms merge to form a covalent bond, allowing electrons to be shared.
Key points
- Understand the mechanism of covalent bond formation according to VBT.
- Differentiate between σ and π bonds.
- Explain the concept of orbital overlap and its relation to bond strength.
- Define and apply hybridization to predict molecular geometry.
Common exam trap
Confusing σ and π bond formation.
Definitions
- Term
Orbital Overlap
- Meaning
The phenomenon where atomic orbitals of two atoms merge to form a covalent bond, allowing electrons to be shared.
- Term
Σ (σ) Bond
- Meaning
A covalent bond formed by the head-on overlap of atomic orbitals along the internuclear axis.
- Term
Π (π) Bond
- Meaning
A covalent bond formed by the lateral overlap of atomic orbitals, typically p-orbitals, above and below the internuclear axis.
- Term
Hybridization
- Meaning
The mixing of atomic orbitals of comparable energies on an atom to produce a new set of degenerate hybrid orbitals with different spatial orientation.
Learning objectives
Understand the mechanism of covalent bond formation according to VBT.
Differentiate between σ and π bonds.
Explain the concept of orbital overlap and its relation to bond strength.
Define and apply hybridization to predict molecular geometry.
Relate VBT to the properties of molecules.
Prerequisites
Atomic Structure
Electronic Configuration
Atomic Orbitals (s, p, d)
Concept of Valence Electrons
Common mistakes
Confusing σ and π bond formation.
Incorrectly predicting hybridization states.
Assuming all bonds in a molecule are σ bonds.
Not considering the role of lone pairs in hybridization.
Overlooking the difference in strength between σ and π bonds.
Keywords
Valence Bond Theory
Orbital Overlap
Σ Bond
Π Bond
Hybridization
sp hybridization
sp2 hybridization
sp3 hybridization
Molecular Geometry
Covalent Bond
Practice preview
In the formation of a double bond between two carbon atoms, one bond is a sigma (σ) bond and the other is a:…
easy
What is the hybridization of the central carbon atom in methane (CH4)?…
medium
The molecule BCl3 exhibits which type of hybridization for the central boron atom?…
medium