This is an interactive Challenge in which students have to find others in the room with whom they "match" as a hard or soft acid or base. It brings to life the way inorganic chemists think about HSAB. Inorganic Challenges are exercises designed to be solved by a small group of students. Some Challenges practice a problem-solving algorithm, some reinforce important concepts, and some involve creativity or games. You can pick and choose Challenges from our Web site to increase active learning in your classroom, and we ask that you contribute creative Challenges of your own to give a head start to teachers at other colleges and universities! Please visit http://chem.rochester.edu/~plhgrp/iicf/subjects.htm
At the end, I ask a few students to introduce to the class their acid or base, and what they found.
Works ok. It's a little silly, but fun.