Atoms are made from protons, neutrons and electrons. The periodic table arranges elements according to their atomic size and other properties, atomic theory and atomic numbers.

One hundred fifty years after Russian chemist Dmitri Mendeleev published his system for neatly arranging the elements, the periodic table it gave birth to hangs in every chemistry classroom in the ...

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 ...