Properties of Covalent and Ionic Compounds 

Students begin thinking about the properties of different compounds from an electron behavior and forces standpoint before naming all compound types in C.2 Electrostatics Lesson 12. They deepen their understanding of compound properties throughout C.3 Space Survival using difference in inter- and intramolecular forces to explain bulk and atomic-level properties. Use of a force-based model to explain properties supports students in a more nuanced understanding of bonding rather than an ionic/covalent binary. 

Naming and Predicting Compounds

The key to students naming compounds is helping them recognize patterns rather than memorizing rules. Our approach is to develop these patterns over time. Students are introduced to compound names as the need for them arises. They encounter a number of ionic compounds in C.2 Electrostatics Lesson 13, with a variety of molecular compounds introduced in C.3 Space Survival and additional compounds named throughout the rest of the course, including hydrocarbons and other carbon-based compounds in C.5 Fuels. Requirements to introduce the rules for naming compounds could be met in these units by helping students draw patterns from similar names and problematize the names of new compounds based on those patterns. 

Across the course, students work to develop science ideas about particle-level interactions, origins or production of compounds, and their applications. Students move beyond a focus on rote predictions of compound formation in C.3 Space Survival to develop a mechanistic, electronegativity-based understanding of why elements combine to form particular compounds. A mechanistic understanding lays a foundation for moving beyond the octet rule, a useful approximation that applies to only a subset of compounds. This model also reduces the need to name common chemical reaction and combustion types, although this could be done as students encounter them in C.3 Space Survival, C.4 Oysters, and C.5 Fuels.