This activity is designed to serve two purposes. The first is to give students practice with assigning the acidity of cations (acidic or non-acidic) and the basicity of anions (basic, feebly basic, or non-basic). The second is to guide students to discover the general trends in solubility for combinations of Bronsted acids and bases. The thermodynamic underpinnings of these generalized "solubility rules" are taught in the subsequent lecture.
Students should be able to classify cations as acidic or non-acidic and anions as basic, feebly basic, or non-basic.
Students should begin to appreciate the relationship between Bronsted acidity and basicity and the solubility of ionic compounds.
I have the students work on the activity in groups and then we discuss it together at the end of class. When I used the activity I was teaching via Zoom, so I had students collaborate with their group in a Google Doc (one page per group) and I followed along while they were in their breakout rooms. I taught my class in a flipped format, so the activity is designed to take a full 50 minute class period*, including introduction, group work, and full class discussion.
*In practice, it took students some time to assign the acidity and basicity of the cations and anions, in part because they defaulted back to quantitative methods (calculating Z2/r and pKb then looking at the textbook) rather than using the qualitative tools from the previous activity. As a result, we spent two 50 minute class periods on this activity.