Introducing Building Block Chemistry Chlorine and chlorine compounds are a good way to introduce your students to building block chemistry without tackling the whole periodic table at once. On its own, chlorine has a distinct odor, although smelling chlorine is not recommended. Liquid chlorine is amber in color. And in low concentrations, chlorine gas is nearly invisible. But when chlorine combines with other elements it does things that will keep students tuned in.
Chlorine compounds can turn blue, brown, or sparkling white.
They can change odor or have none at all. They can be hot or cold. They can bubble, liquefy, or harden. Household bleach, or sodium hypochlorite, is the secret ingredient that clears up the water. Once the secret is out, point to the poster to launch a hunt for all the unexpected things chlorine compounds help build.