CHEMISTRY Name_______________ Date ________ Period __ Lab: Molecular Models Introduction: Lewis electron dot structures and molecular models are useful ways to visualize the bonding in molecules. All of the models will follow the octet rule. Exceptions to the octet rule are hydrogen and helium, since each atom can hold only two valence electrons. Thus, hydrogen and helium follow the duet rule. Purpose: to become familiar with the three-dimensional shapes of molecules. to draw electron dot diagrams for simple and complex molecules. to build molecular models from electron dot diagrams. Prelab: Write your answers in your lab notebook. 1. Draw electron dot diagrams for elements 1 through 18. 2. Draw electron dot structures for the following molecules. a. b. c. d. e. hydrogen gas, H2 water, H2O oxygen gas, O2 methane, CH4 nitrogen gas, N2 Materials: molecular model kit gum drop candies miniature marshmallows toothpicks Safety: Do not eat lab materials! Do not put toothpicks in the eyes or mouth! Procedure: Part I: Molecular Model Kit 1. Using the molecular model kit, build models of the five molecules listed in the prelab: hydrogen gas, water, oxygen gas, methane, and nitrogen gas. 2. Draw a sketch of the model in your lab notebook. 3. Show each model to the instructor for approval before disassembling. Part II: Candy Creations 1. Draw Lewis structures for the following molecules: a. b. c. d. e. f. g. h. CH2Cl2 Cl2 HOCl NH3 OHH 3O + NH4+ SO42- i. j. k. l. m. n. o. p. C2H6 CO2 H 2O 2 C2H4 SO2 SiH4 PH3 O3 q. r. s. t. u. v. HCN CH3F CH2O CO32H 2S C2H5OH 2. Collect gumdrops, marshmallows, and toothpicks. The gum drop candies and marshmallows will be used to represent individual atoms. Toothpicks will be used to represent single bonds, or a pair of shared electrons. Double bonds will require two toothpicks, and triple bonds will require three toothpicks. 3. Build models of molecules a, d, i, j, q, and v listed above. 4. Show each model to the instructor for approval before disassembling. Part III: Extension (optional) Choose one of the following: 1. Select one of the following molecules and build a model. You may use the materials provided, or choose your own. ibuprofen, C13H18O2 acetaminophen, C8H9NO2 aspirin, C9H8O4 2. Research (textbook, internet, etc) and select your own molecule to build (must contain at least 8 atoms). You may use the materials provided, or choose your own.