Students get hands-on with elements, compounds, atoms, and molecules in this activity. This should be used after students have been introduced to elements and compounds to build a stronger understanding of the relationship between elements/compounds and atoms/molecules.
First, students classify the substances (using their chemical formulas) by Kind of Particle (atom or molecule) and then by Kind of Substance (element or compounds). Then, they get to use manipulatives (such as legos or any other colored manipulative that can attach to each other) to build the atoms and molecules so they can better observe the similarities and differences.
Afterward, the analyzation questions serves as a good formative assessment of their mastery of the topic.
This can be used during the chemistry unit in any middle school grade level, or even in high school Chemistry.