Untitled - Kelly Walsh High School

Molecular Geometry and Hybridization 149
Don’t Forget!
In using the VSEPR theory to determine the molecular geometry, start first with
the electron group geometry, make the nonbonding electrons mentally invisible
and then describe what remains.
10-2 Valence Bond Theory (Hybridization)
VSEPR theory is one way to determine the molecular geometry. Another
method involves using valence bond theory. Valence bond theory describes
covalent bonding in terms of the blending of atomic orbitals to form new types
of orbitals, hybrid orbitals. Hybrid orbitals are orbitals formed due to the combining
of the atomic orbitals of the central atom. The total number of orbitals
does not change. The number of hybrid orbitals equals the number of atomic
orbitals used. The type of hybrid orbitals formed depends on the number and
type of atomic orbitals used. Figure 10-3 shows the hybrid orbitals resulting from
the mixing of s-, p-, and d-orbitals. The atoms share electrons through the overlapping
of their orbitals. Any combination of overlapping orbitals is acceptable.
Figure 10-3 Hybridization of s-, p-, and d-orbitals
sp hybridization results from the overlap of one s-orbital with one p-orbital. Two
sp hybrid orbitals form with a bond angle of 180o . This is a linear orientation.
sp2 hybridization results from the overlap of one s-orbital with two porbitals.
Three sp2 hybrid orbitals form with a trigonal planar orientation and