Grade Levels: 10-12 chemistry students
The student will be able to predict bond type, structural formula, hybridization, polarity, and three-dimensional structures using ball and stick models.
Maine Learning Results objectives:
Science and Technology
E. Structure of Matter ? Students will understand the structure of matter and the changes it can undergo. Students will be able to describe how atoms are joined by chemical bonding.
L. Communication ? Students will communicate effectively in the application of science and technology. Students will be able to make and use appropriate symbols, pictures, diagrams, scale drawings, and models to represent and simplify real-life situations and to solve problems.
L. Communication ? Students will communicate effectively in the application of science and technology. Students will be able to critique models, stating how they do and do not effectively represent the real phenomenon.
Materials & Resources:
Lab-Aids - Molecular Model Kit
Student worksheet ? Bonding Lab
Internet site: http://www.eosc.osshe.edu/chemweb/main.html
1. Bond Type ? Ionic or Covalent
2. Lewis Dot Diagrams ? use to initialize thought about the molecule
3. Structural formula ? Similar to Lewis dot diagram, but use lines to represent a bond between a covalent molecule and do not show non-bonding electrons.
4. Hybridization should be shown on the structural formula.
5. Three-dimensional representation should be drawn. A tetrahedral representation should be a 4-sided pyramid (see example on worksheet).
6. Polarity ? any dipole moment should be shown on the drawing.
7. Internet address ? Go to site and click on Molecular Modeling. Go to the bottom of the page and click on the ">>" to proceed to a listing of the contents of the site. Click on Relationship of Molecular Shape to Electron Pair Geometry. Students should then view each example and Diagram for the sample molecules. This action should be done only if the students cannot determine the required information. It may also be used as a reinforcement for prior information.
Have students produce a write-up in a lab notebook or whatever format you choose. The bond type, Lewis Dot Diagram, structural formula, hybridization, and 3-D representation should be given for each molecule.
The teacher will demonstrate the concept of molecular modeling and knowledge of structure based on models. Students will be able to predict structures, polarity, hybridization, and arrangement of atoms within a molecule.
Molecular Bonding Lab
Use the model kits as needed to determine the structure for the following compounds.
CH3Cl H2O CH4 Cl2
H2S CO2 NH3 NH4+
HCl HNO3 H2SO4 HCCl3
C2H6 SO2 CH2O
For the lab write-up:
1) Indicate bond type (covalent or ionic)
2) Give Lewis Dot Diagram
3) Show Structural formula (covalent only)
4) Indicate hybridization (if applicable)
5) Give 3-D representation for compounds and give proper names for the structure.
1) Show polarity by d+ or d- and show any dipole moment where applicable.
Key for Model Kits:
Red -- Nitrogen
Green -- Chlorine
Blue -- Oxygen
Yellow -- Sulfur
White -- Hydrogen
16 Plastic covalent bonds
1 Plastic electron bond