Name: _________________________________
Date: _____________ Period: ____
Lab – Molecular Models
Introduction:
Lewis structures can be used to predict molecular and ionic geometries (shapes), as well as polarity.
Generally, atoms have eight electrons in their outer shell (octet rule). In addition, valence electrons exist in
electron domains around atoms in either bonded pairs or non-bonded (lone) pairs. These electron domains
can be used to predict the overall geometry of a molecule because electrons repel each other. This method is
termed valence-shell electron-pair repulsion (VSEPR) theory. Each electron pair occupies as much space
around the nucleus and inner electron shells of the atom as it can, and excludes other electrons from
occupying the same space, a consequence of the Pauli Exclusion Principle.
In addition to VSEPR theory, orbital hybridization can be used to predict overall electron domain
geometry (includes atoms and electron domains) as well as molecular geometry. A hybridization (blending)
of s and p orbitals can occur when low energy electrons are promoted to higher energy levels, resulting in a
blended orbital of the participating orbitals (i.e., sp, sp2, sp3).
In this lab, you will construct molecules from Lewis structures, and correlate molecular shapes with
orbital hybridizations.
Materials: molecular models kits
Methods and Analysis:
Construct each of 24 molecular species, and then complete a data table including the following:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Total valence electrons
Lewis structure
Total # of electron domains
# of non-bonded (lone) electron pairs
ABmEn category
Predicted overall electron domain geometry
Predicted molecular geometry (shape)
Predicted bond angle(s)
Orbital hybridization (if applicable)
Symmetry (symmetrical or asymmetrical)
Polarity (polar or nonpolar)
Resonance (yes or no)
Tips for Modeling Kit: (refer to these tips frequently throughout the lab)
-Yellow wood spheres are H and any atom forming only one bond (like F, Cl, etc.).
-Red wood spheres are usually O, but not when O is central (2 lab groups will use red clay spheres).
-Black wood spheres can be any atom with 4 domains: 4 bonds, 3 bonds and 1 E pair, 2 bonds and 2 E pairs.
-Purple or Orange wood spheres are for lone E pairs on the central atom (other e– need not be modeled).
-If more 3, 5, or 6 domains (bonds and E pairs) are needed, choose a clay sphere as the central atom.
1
Total
Lewis Structure:
Valence
Electrons:
H2 O
8
OR
Total # of
Electron
Domains:
4
# of Lone
Electron
Pairs:
2
ABmEn:
AB2E2
Total
Lewis Structure:
Valence
Electrons:
HCN
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
NH3
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
CCl4
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Electron Domain
Geometry:
tetrahedral
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
bent
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
109.5o (or 104.5o)
Hybridization
(or N/A): sp3
Resonance (more than
one identical structure):
Yes or No
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
2
Total
Lewis Structure:
Valence
Electrons:
CF2Cl2
(CFC
or
chlorofluorocarbon)
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
BF3
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
SCl4
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
SF6
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
3
Total
Lewis Structure:
Valence
Electrons:
SO2
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
PCl5
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
XeF4
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
IF5
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
4
Total
Lewis Structure:
Valence
Electrons:
CO2
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
NO2
–
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Total
Lewis Structure:
Valence
Electrons:
BrF3
Total # of
Electron
Domains:
___
# of Lone
Electron
Pairs:
___
ABmEn:
______
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Electron Domain
Geometry:
_____________
Symmetrical
or
Asymmetrical
Molecular
Geometry (Shape):
_____________
Polar Molecule/Ion
or
Nonpolar Molecule/Ion
Bond Angle(s):
Resonance (more than
one identical structure):
Yes or No
Hybridization
(or N/A):
Conclusion:
Write a brief conclusion describing what you have experienced regarding VSEPR theory and molecular
geometry. Include related concepts like number of domains and hybridization, and symmetry and polarity.
5