Hybrid Atomic Orbitals

Wave Function (ψ)

A mathematical expression in quantum mechanics that describes an orbital and the wavelike properties of electrons in an atom.

Hybridization

The process of combining atomic orbital wave functions to form new orbitals with different shapes, explaining molecular bonding more accurately.

Linear Combination of Atomic Orbitals (LCAO)

The mathematical technique used to form hybrid orbitals by combining wave functions of atomic orbitals.

Hybrid orbitals

New orbitals formed from the combination of atomic orbitals: in oxygen with water, 4 equivalent hybrid orbitals point toward a tetrahedron’s corner.

109.5°

Bond angle in an ideal tetrahedral geometry.

104.5°

Observed bond angle in water molecule

Due to the lone-pair repulsions

Why is the observed bond angle slightly less than the tetrahedral angle?

To account for differences between simple orbital overlap predictions and experimentally observed bond angles.

Why does the valence bond theory need hybridization?

Isolated atoms

Hybrid orbitals do not exist in…

Covalently bonded atoms

Hybrid orbitals are only formed in…

shapes, orientations

Hybrid orbitals have _____ and ___________ that are very different from those of the atomic orbitals in isolated atoms

Yes it is true

Is it true that the number of hybrid orbitals in a set is equal to the number of atomic orbitals that were combined to produce the set.

shape, energy

All orbitals in a set of hybrid orbitals are equivalent in _____ and ______

electron-pair geometry

The type of hybrid orbitals formed in a bonded atom depends on its _____________________

σ bond

The bond that gets formed when hybrid orbitals overlap.

π bond

The bond that gets formed when unhybridized orbitals overlap.

Beryllium atom in a gaseous BeCl2 molecule

An example of a central atom with no lone pairs of electrons in a linear arrangement of three atoms.

Linear (180° bond angle, no lone pairs on Beryllium)

Electron geometry of BeCl2 molecule.

Two (corresponding to the two Be-Cl bonds)

Number of regions of valence electron density in BeCl2

One s orbital + one p orbital = two sp orbitals

What orbitals mix in Be hybridization for BeCl2

Two sp orbitals

Number of hybrid orbitals formed when Be mixes s and p

Number of orbitals combined = Number of hybrid orbitals formed

Rule for hybridization

Linear, pointing 180° apart

Shape/orientation of sp hybrid orbitals in BeCl2