New AACT Resources to Help Teach Chemical Bonding

As chemistry teachers around the country plan activities for their students, AACT will highlight resources from our high school resource library that can be used to reinforce topics in different units throughout the school year. Our last post highlighted resources to support a Periodic Table unit. We will now focus on new AACT resources to use in a Chemical Bonding unit plan.

We have added two resources that help students model covalent bonding and polarity with the use of string and Styrofoam balls.

• In the activity, Modeling Bond Polarity students model the pull of electrons in a bond between two elements, demonstrating covalent bonding. In particular differentiating between polar and nonpolar bonds.
• In a similar activity, Modeling Molecular Polarity, students use electronegativity values and their knowledge of covalent bonding to model the bonds in a molecule. They then use that information to help them determine the overall polarity of a molecule.

There are also two new resources related to the topic of intermolecular forces (IMFs) in our high school library:

• An Exploration of Intermolecular Forces will allow your students understand the strength of the attractions of the three intermolecular forces (IMFs) through an introductory demonstration and review activity. They then use this information to help identify physical properties of molecules with a follow up lab. This resource was written by the 2018 AP Chemistry Content Team and has recently been updated with alignment to the new College Board Course Framework.
• The activity, Examining the Strength of Intermolecular Forces of Attraction helps students understand the strength of the attractions of the three types of IMFs and use this information to help identify physical properties of molecules, such as melting point, boiling point or states of matter.

Before teaching your students about IMFs, you probably cover the topic of molecular shapes and VSEPR. You may want to use one or both of these new resources to help your students visualize the topic.

• Students can explore Valence Shell Electron Pair Repulsion Theory using the activity, VSEPR with Balloons. Balloons tend to take up as much space as they can when tied together, so they look like models of central atoms in VSEPR theory, making a great metaphor for the model. This resource is an extension of the AACT activity, Shapes of Molecules.
• In the activity, Discovering Molecular Shapes, students manipulate connected strings and a computer simulation to discover how electron-electron repulsion determines the 3D VSEPR geometric shapes of simple covalent molecules. This allows them to practice drawing Lewis structures as well as deepen their understanding of the connection between a molecule’s structure and its shape.

Finally, if you are looking for a resource that can serve as a culminating activity for your covalent bonding unit, look at the activity, Properties of Common Molecular Substance. This resource allows students to apply their knowledge of molecular polarity, shape, and intermolecular forces to explain the differences in properties between different covalent substances. It was inspired by the Molecular Modeling project and is a good substitute for those who do not have the time for students to complete a long-term project.

We hope that these activities can help you to reinforce several of the topics covered in a unit about Chemical Bonding. Most of these lessons were made possible by great teachers who shared their own resources. We need your help to keep the collection growing. Do you have a great demonstration, activity, or lesson related to this topic that you would like to share with the community? Please send it along for consideration.