Geometrical Structure of Molecules

In this lab we are going to use ball and stick models to determine the actual shapes of some molecules. After constructing the Lewis Structure of each molecule, you will then use molecular modeling kits to build the 3-D representation and identify the actual shape. We will assume for this lab that if the "octet ruler" is not followed, then the molecule is unstable.

The concept for building these molecules is simple:

1. The color of the ball to use is shown on the lid of the box. Make sure you use the correct color for each atom involved. If you do not have enough of any one color, borrow from someone else—just RETURN it later!

2. To make a valid model, all holes must be filled. They can be filled with a bond connected to another atom or with a lone pair of electrons.

3. If you need to make a multiple bond, use the LOOOONGER links, and for single bonds use the short links.

4. This will be fun! However, they are not designed to be thrown around the room.

PROCEDURE:

  1. Draw Lewis Structures for each of the molecules shown.
  2. Build the actual model.
  3. Do your very best to draw what you see for the 3D model and put this in your lab notebook.
  4. Answer any follow-up questions for each set such as Shape Name, Bond Angle(s), Polararity, etc (varies for each one).

Molecule: Draw Lewis & 3D Model / Additional Info to Record: / Molecule: Draw Lewis & 3D Model / Additional Info to Record:
CH4 / Shape Name, Bond Angle(s), Polar/Nonpolar / NH3 / Shape Name, Bond Angle(s), Polar/Nonpolar
CH3Cl / Shape Name, Bond Angle(s), Polar/Nonpolar / BCl3 / Shape Name, Bond Angle(s), Polar/Nonpolar
CH2Cl2 / Shape Name, Bond Angle(s), Polar/Nonpolar / SF6 / Shape Name, Bond Angle(s), Polar/Nonpolar
CHCl3 / Shape Name, Bond Angle(s), Polar/Nonpolar / XeF4 / Shape Name, Bond Angle(s), Polar/Nonpolar
H2O / Shape Name, Bond Angle(s), Polar/Nonpolar / CH4O / (None)
N2 / Shape Name, Bond Angle(s), Polar/Nonpolar / H2O2 / (None)
CO2 / Shape Name, Bond Angle(s), Polar/Nonpolar / C2H2Br2 / Draw 2 Isomers: Same formula but different structures
HF / Shape Name, Bond Angle(s), Polar/Nonpolar / C2H4 / (None)
PCl4-1 / Shape Name, Bond Angle(s), Polar/Nonpolar / C2H2 / (None)

POST LAB:Which of the following would be stable (actually form): PCl3, CH3,OH,CO. Why?