Khan Academy
Khan Academy: Biology: Chemistry of Life: Matter, Elements, and Atoms
Did you know matter is made up of atoms? In this article learn about the smallest unit of matter called the atom.
Khan Academy
Khan Academy: Biology: Chemistry of Life: Atomic Number,atomic Mass,and Isotopes
Learn the fundamental properties of atoms in this article. Understand the definition of atomic number, atomic mass, and isotopes. [6 min, 50 sec]
Khan Academy
Khan Academy: Biology: Chemistry of Life: Chemical Reactions
An article discussing how chemical reactions make and break bonds between atoms.