All matter in the observable universe—from a single blade of grass to a planet in a faraway galaxy—is made up of atoms, molecules, and compounds. This program introduces these minuscule building blocks in five sections: The Nucleus (protons and neutrons, energy shells, binding energy, fission and fusion); The Electrons (quantum numbers, spdf orbitals); The Elements (periodic table, valence electrons, ions and ionization energy, electronegativity, covalent and ionic bonds); The Energy of Atoms (exothermic and endothermic reactions, spontaneous reactions, Gibbs free energy, activation energy, catalysts); and Common Compounds (properties of sodium chloride and water, polarity). A viewable/printable instructor’s guide is available online. A Films for the Humanities & Sciences Production. A part of the series Essential Chemistry. (25 minutes)

One hundred thousand times smaller than the atom is its nucleus, a densely packed area of positively charged protons and neutral neutrons. Each chemical element has distinct characteristics based on its electrons, protons, and neutrons.

Inside the electron cloud, negatively charged electrons are attracted to the positively charged nucleus. Moving clouds of electrons enable atoms to bond with other atoms. Concepts of fission and fusion are defined and illustrated.

In atoms, electrons govern most of the everyday world. Electrons circle in "shells" that revolve around the protons and neutrons of the nucleus. Vocabulary: S, P, D, and F orbitals, and principal quantum number.

The periodicity of the elements is due largely to recurring patterns in their electron configuration. Valence means the number of electrons an atom must lose or gain to complete its outermost orbital. Vocabulary: ionization energy, electronegativity.

Chemical reactions are of two main types: exothermic and endothermic. Gibbs free energy measures the energy to do work or potential energy. Activation energy is the added energy needed to activate some reactions.

Chemists use their knowledge of atoms and molecules to better understand the day-to-day world around us. Salt, a compound of sodium and chloride atoms, is hydrophilic--it attracts water.