CH 9 COVALENT
BONDING ORBITALS
AP Chemistry
2014-2015
HYBRIDIZATION AND THE LOCALIZED
ELECTRON MODEL
The localized electron model
(from Chapter 8) views a
molecule as a collection of
atoms bound together by
sharing electrons between
their atomic orbitals. For
example, methane (CH 4 )
consists of one carbon atom
bonded to four hydrogen
atoms.
 According to the orbital diagram for carbon, there are
four valence electrons—two in the 2s subshell, and two
in the 2p subshell.
 One of the 2s electrons can get “promoted” to the 2p
subshell. This move allows carbon to form four bonds,
one to each hydrogen. However—this would mean that
the four C-H bonds are not identical. Experimental
observations show that the four C -H are identical, so
this model does not correctly explain every aspect of
bonding.
We can modify it, though, so that carbon’s 2s
and three 2p orbitals “hybridize” to form four
identical sp 3 orbitals.
OVERVIEW OF HYBRID ORBITALS
Type of Hybridization
sp
sp2
Orbital Composition
1s
1p
1s
2p
Number of Electron
Domains
Common Molecular
Geometries
2
Linear
3
sp3
1s
3p
4
dsp3 (also sp3d)
1s
3p
1d
5
d2sp3 (also sp3d2)
1s
3p
2d
6
Trigonal planar
Bent
Tetrahedral
Trigonal pyramidal
Bent
Trigonal bipyramidal
See-saw
T-shaped
Linear
Octahedral
Square pyramidal
Square planar
T-shaped
Linear
SP HYBRIDIZATION
Hybridization of one s orbital and one p orbital
Two electron domains
Usually occurs when an atom either a) forms
double bonds to two different atoms (ex. CO 2 )
or b) forms a single bond to one atom and a
triple bond to another atom (ex. HCN). One
exception to this is beryllium hydride, BeH 2 .
Ex. CO 2 , HCN, C 2 H 2 , N 2 , BeH 2
SP 2 HYBRIDIZATION
Hybridization of one s orbital and two p
orbitals
Three electron domains
Usually occurs when an atom forms single
bonds to two atoms, and a double bond to a
third atom
(ex. CH 2 O). One exception to this is boron
trifluoride, where boron forms single bonds
with three atoms (no double bonds).
Ex. C 2 H 4 , CH 2 O, BF 3
SP 3 HYBRIDIZATION
Formed by the hybridization of one s orbital
and three p orbitals
Four electron domains
Ex. CH 4 , NH 3 , H 2 O
DSP 3 HYBRIDIZATION
Hybridization of one s orbital, three p orbitals,
and one d orbital
Five electron domains
Ex. PCl 5 , I 3 -
D 2 SP 3 HYBRIDIZATION
Hybridization of one s orbital, three p orbitals,
and two d orbitals
Six electron domains
Ex. SF 6
FOR EACH OF THE
FOLLOWING MOLECULES,
WRITE THE LEWIS
STRUCTURE, PREDICT THE
MOLECULAR STRUCTURE,
GIVE THE EXPECTED HYBRID
ORBITALS ON THE CENTRAL
ATOM, AND PREDICT THE
OVERALL POLARITY.
Molecule
NF3
TeF4
Lewis Structure
Molecular
Structure
Hybridization
of Central
Atom
Overall
Polarity
Molecule
KrF2
SeF6
Lewis Structure
Molecular
Structure
Hybridization
of Central
Atom
Overall
Polarity
Molecule
IF3
Lewis Structure
Molecular
Structure
Hybridization
of Central
Atom
Overall
Polarity
DETERMINE THE HYBRIDIZATION OF EACH
ATOM IN THE FOLLOWING MOLECULES .
DETERMINE THE HYBRIDIZATION OF EACH
ATOM IN THE FOLLOWING MOLECULES .