Chemistry is the study of all matter, but matter at the very particular scale of atoms and molecules; Professor Davis begins by outlining his approach to this topic; introducing the periodic table of elements, which is a powerful conceptual tool.

Chemists have convenient units for dealing with matter at the atomic scale; learning the origin and relative size of the angstrom to measure length; the atomic mass unit; the mole for measuring quantity; the Kelvin scale for temperature.

Investigating what is inside the atom; how electrons, protons and neutrons are distributed; how they give an atom its identity; how they affect its electrical charge and atomic mass; the meaning of terms such as isotope, anion and cation.

How electrons organize themselves within the atom depending on their energy state; graduating from Niels Bohr's model of the atom to Erwin Schrödinger's more precise theory; charting different electron configurations in heavier atoms.