Title: Molecular Models
Purpose: The chemistry student will use three dimensional molecular model kits to determine
various physical characteristics of selected compounds. In addition the student will draw Lewis
Dot Structures and structural formulas for each compound or polyatomic ion.
Materials:
Models, pencil, paper, electronegativity table, bond type table
Procedure:
1.The student will draw columns horizontally with a ruler on paper to include the following;
substance, LDS, SF, Bond Type, Bond Angle, Molecule Polarity, and Model.
2.For each of the following substances, NH4+, NH3, H2O, H2S, H2, HCl, PCl3, CO2, C2H4, ClO3-,
the student will determine the Lewis Dot Structure, Structural Formula, Bond Type (nonpolar,
polar, ionic), Bond angle, and the polarity of the molecule. This will be recorded on their paper.
They will build a model of the substance according to the instructions on the kit. They will build
as many of the listed models as possible until they run low on parts. At that time they willng the
models and the sheet for the instructor to see and sign in the model column. Make certain all
information is complete when brought to the instructor. Repeat this process if needed until all
models are completed.
Questions:
1. Explain the difference between a nonpolar covalent bond and a polar covalent bond.
2. Explain how a molecule can be composed entirely of polar bonds but still be a
nonpolar molecule.
3. Explain why a glass rod would attract the molecules in a stream of water, but not
carbon tetrachloride (CCl4).
4. Why are ionic substances composed of formula units and not molecules?
5. State the bond type for each of the following: OCl2, HClO3, K2S, BF3, SiO2.
6. State which of the following that would be the best example of H-bonding, polar covalent
bonding, metallic bonding, ionic bonding, nonpolar covalent bonding.
BaCl2
Conclusion:
Fe
PS3
RNA
SO3