UTPA STEM/CBI Courses/Molecular Structure

Course Title: General Chemistry 1301

Lecture Topic: Molecular Structure

Instructor: James Bullard

Institution: University of Texas-Pan American

Backwards Design

Course Objectives

• Primary Objectives- By the next class period students will be able to:
  • Understand molecular geometry
  • Understand VSEPR
  • Understand various geometries

• Sub Objectives- The objectives will require that students be able to:
  • Draw Lewis structures and use the structure to determine electron domain geometry.
  • Understand that electron domains are used to determine molecular geometry.

• Difficulties- Students may have difficulty:
  • Memorizing Geometries
  • Memorizing shapes

• Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
  • To understand the concept of theories.
  • Develop their ability to think conceptually.

Model of Knowledge

• Concept Map
  • Draw Lewis structure
  • Count the number of electron domains on the central atoms
  • Determine the electron-domain geometry (The electron-domain geometry is based on the number of electron domains around the central atom)
  • Determine the molecular geometry (the electron domain geometry and the number of bonded atoms **determine the molecular geometry)

• Content Priorities
  • Enduring Understanding
    • Working with edible models (marshmallows and pretzels)
    • Understand how the molecular geometry of molecules are predicted
  • Important to Do and Know
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  • Worth Being Familiar with
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Assessment of Learning

• Formative Assessment
  • In Class (groups)
    • Solve geometry from Lewis structure
    • Determine bond angles from geometry
  • Homework (individual)
    • Homework assignment for in class discussion
• Summative Assessment
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Legacy Cycle

OBJECTIVE

By the next class period, students will be able to:

• Understand VSEPR
• Understand various geometries
• Understand electron domains and how they are used to predict molecular geometry
• Understand how to predict molecular geometry

The objectives will require that students be able to:

• Determine electron domains and use this knowledge to develop electron domain geometries. This can be used to understand what bond angles are possible and why there are different set bond angles.
• Use the knowledge of electron domain geometries to predict molecular geometries.

THE CHALLENGE

Students will be asked to develop three-dimensional, molecular models using junk food.

GENERATE IDEAS

What can be used for different electron domains? What is then used for molecular structures?

MULTIPLE PERSPECTIVES

Different groups can brainstorm to come up with different ideas for junk food that can be used to construct models.

RESEARCH & REVISE

Know all possible shapes from the textbook.

TEST YOUR METTLE

Each group member develops a design for a different molecule.

GO PUBLIC

Display and explain to the rest of the class.

Pre-Lesson Quiz

1. What are valence electrons?
2. Define covalent bonds.
3. How does bond length effect bond strength?
4. Define the steps for drawing Lewis structures.
5. Draw Lewis structures of five given compounds.

Test Your Mettle Quiz

1. Define electron domains.
2. Is a triple bond a larger electron domain than a double bond?
3. Why can’t we “see” an electron domain formed by a lone pair in a molecular structure?
4. How do lone pairs effect molecular geometry?
5. Can there be the electron domain structure be the same as molecular geometry? When?