Worksheet 14 - Hybridization
The hybridized molecular orbitals have different shapes and energy levels than the
atomic orbitals. The number of molecular orbitals created by hybridization depends on
the number of atomic orbitals that are mixed to form them.
In forming sp3 hybridized orbitals, four atomic orbitals are mixed, one s and three p.
The energy diagram for this process is shown below. The hybridized orbitals are higher
in energy than the s orbital, but lower in energy than the p orbitals.
p
energy
sp3
hybridization
s
atomic orbitals
hybridized orbitals
Carbon has 4 valence electrons. Add these electrons to the atomic and molecular
orbitals. This hybridization gives tetrahedral geometry.
With this hybridization, C will form four equivalent σ bonds.
Draw a similar energy diagram for sp3 hybridized oxygen.
p
energy
sp3
hybridization
s
How many σ bonds will be formed?
How are the other sp3 orbitals used?
2
The other sp3 orbitals hold the
oxygen lone pairs
Do the same for sp3 hybridized nitrogen.
p
energy
sp3
s
hybridization
In some Lewis structures, there are only three equivalent bonds formed. To create
three equivalent hybridized orbitals, mix three atomic orbitals.
Draw and name the orbitals formed in this hybridization, then add the electrons for
sulfur. Since the hybridized orbitals are close in energy, every orbital is filled with one
electron before electrons are paired.
p
p
sp2
energy
hybridization
s
The hybridized orbitals will form __1___ σ bond(s).
The unhybridized orbital will form __1___ π bond(s).
There will be __2___ lone pair(s).
This hybridization gives trigonal planar geometry.
In linear molecules, like CO2, the central atom has only two equivalent bonding orbitals.
Draw the energy levels and name the orbitals formed in this hybridization.
p
p
sp
energy
hybridization
s
Fill in the electrons for carbon and determine the number and type of bonds formed.
There will be 2 sigma bonds (with sp) and 2 pi bonds (with p)
In CO2, determine the hybridization of the oxygen atoms. Complete the energy
diagram for the oxygens. Draw the structure of CO2.
p
p
sp2
energy
: :
hybridization
: :
s
O C O
Each oxygen atom forms 1 sigma bond (with the sp2) and 1 pi bond
(with the p) with the sp and p orbitals on the carbon atom
In atoms with n=3 or larger, the d orbitals can also be hybridized. In molecules with five
molecular orbitals, five atomic orbitals are mixed:
_d_ + _s_ + _p_ + _p_ + _p_
This will give trigonal bipyramidal geometry and is called dsp3 hybridization.
Finally, molecules with octahedral geometry, will have __6 __ molecular orbitals. This
2
3
hybridization is called __d sp ______ .
Shown below is a portion of the chart from Worksheet 13. Fill in the hybridization for
each of the compounds.
compound
bonds
lone
pairs
geometry
shape
hybridization
bonds + lone pairs = 6
SF6
6
0
octahedral
octahedral
d2sp3
bonds + lone pairs = 4
NH3
3
1
tetrahedral
trigonal
pyramidal
sp3
bonds + lone pairs = 6
ICl4
-
4
2
octahedral
square
planar
d2sp3
bonds + lone pairs = 4
CF4
4
0
tetrahedral
tetrahedral
sp3
bonds + lone pairs = 3
SO3
3
0
trigonal
planar
trigonal
planar
sp2
bonds + lone pairs = 5
SF4
4
1
trigonal
bipyramidal
seesaw
dsp3
bonds + lone pairs = 2
CO2
2
0
linear
linear
sp
bonds + lone pairs = 4
H2O
2
2
tetrahedral
V-shaped
sp3
bonds + lone pairs = 3
NO2
-
2
1
trigonal
planar
V-shaped
sp2
Fill in the chart below and then complete the Lewis structures for the molecules shown
below and fill in those charts.
element Lewis symbol # bonds # lone pairs
C
4
0
C
N
N
H
H
O
O
Halogen
F
1
H O
3
1
1
0
2
2
1
3
σ bonds __7__
H C C O H
3 2
H
acetic acid
π bonds __ 1__
atom #
1
2
3
bond angle hybridization
120
sp2
109
sp3
120
sp2
H
H
C C
H 3
C
2
N
1
σ bonds _6___
π bonds _3___
acrylonitrile
atom #
1
2
3
bond angle hybridization
180
sp
180
sp
120
sp2
H
2
O H C H
H C N C C N
C H
H C
C
N 1
O
N
H
H C
3
H
H
caffeine
σ bonds 25__
π bonds 4__
atom #
1
2
3
bond angle hybridization
120
sp2
120
sp2
109
sp3
The molecule shown to the left is riboflavin
(vitamin B2). Answer the following questions
about its structure.
a)
how many carbons are sp3 hybridized? 8
H
H O C H
H C O H
H O C H
H C O H
H
H
H
C
H
sp hybridized? 0
H C H
H H C H
H
H C
sp2 hybridized? 10
C
C
C
C
C
C
N
N
C
C
H
N
C
How many nitrogens are sp3 hybridized? 2
b)
C O
N
sp2 hybridized? 2
sp hybridized? 0
H
O
How many oxygens are sp3 hybridized? 4
c)
sp2 hybridized? 2
sp hybridized? 0
d)
How many σ bonds are there in total? 52
e)
How many π bonds are there in total? 7
f)
Which of the three rings are planar?
The ring on the left, in which all carbon
atoms are sp2 hybridized
The acetate ion, C2H3O2- , has both oxygens bonded to the same carbon.
a)
Draw the Lewis structure and all resonance forms.
H
O
C
C
O
H
H
O
sp3
sp2
H
C
C
O
H
sp3
H
sp2
b)
Label the hybridization around each carbon.
c)
Pick one resonance structure and label the hybridization of each oxygen.
d)
How many σ and π bonds are present? 6 sigma bonds, 1 pi bond
e)
Which atom carries the formal negative charge? the oxygen with 3 lone pairs