Valence Shell Electron Pair Repulsion Theory (VSEPR)

Molecules are 3-Dimensional in shape. The overall shape depends on the number of electron regions. Molecular polarity and many chemical properties are dependent on VSEPR theory.

Standard 1- Basic operations and concepts
Standard 2- Social, ethical, and human issues
Standard 3- Technology productivity tools
Standard 4- Technology communications tools
Standard 6- Technology problem-solving and decision-making tools

Standard 1- The student accesses information efficiently and effectively
Standard 2- The student evaluates information critically and competently
Standard 3- The student uses information accurately and creatively

Reside at the heart of the discipline
Interactions of matter and the nature of physical and chemical properties.

Represents a big idea having enduring value beyond the classroom:
Molecules are 3-dimensional. Even on the smallest of scales perspective matters.

Require uncoverage, meaning that misconceptions need to be identified and clarified:
Double bonds represent only one region of electrons. Lone Pair electron regions are more spread out than bonded electron regions.

Offer potential for engaging students:
Possibility of engineering specific chemical for specific jobs. Student will use balloons to model the variety of molecular shapes.

Exit cards, journal responses, and the construction of a 3-dimensional model will each be utilized in this unit. Exit cards will be used after the introduction of a new concept so that the instructor may evaluate the need for reteaching or redirecting the students. In journal responses the teacher should look for statements that would indicate an incorrect understanding or misconception. The 3-D model should represent the basic principles of VSEPR and should demonstrate a particular molecular geometry.

Engagement / Exploration
Beginning with some simple Lewis structures ask the students to predict molecular polarity of several compounds. The students should respond with a justification for their prediction. Go over the true results and ask if the students can develop a reason for the discrepancies.

Explanation
The reason is that molecules are 3-D and Lewis structures can only represent compounds in 2-D. Continue with a set of notes that discuss expanded and contracted octets.

Extension
In small groups or pairs students will randomly draw a card on which is an ion or compound. The students will draw the proper Lewis structure and then construct a balloon representation of the ion or compound. They will then present their model to the class describing the overall shape and identifying its polarity.
Students will be asked to construct a permanent 3-D representation of a molecular geometry.

Evaluation
Students will present their model and compound to the class pointing out molecular polarity and molecular geonetry. A short quiz and the presentation will both be utilized to check the student's understanding and ability.

Information Manager
Effective Communicator
Numeric Problem Solver
Creative and Critical Thinkers
Ethical and Responsible Workers
Resource Manager
Systems Manager
Cooperative Workers
Effective Leader