Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

The periodic table of chemical elements hangs in front of chemistry classrooms worldwide and is an icon for science. Yet much was unknown about its history -- until now. The periodic table reflects ...

Editor's note: The following is a text-only version. The complete version with artwork is available for purchase here (PDF). The periodic table of the elements is one of the most powerful icons in ...