Article explains the experiments on the photoelectric effect and how these experiments led to the idea of light behaving as a particle of energy called a photon.

This lesson will explain that protons are positively charged particles having a mass of one amu and are found in the nucleus of the atom. It is 2 of 3 in the series titled "Subatomic Particles: The Proton."

Discover the life and contributions of Niels Bohr.

This lesson will define an ion and explain what happens if the number of electrons in an atom changes. It is 2 of 3 in the series titled "Ions."

This lesson will define an ion and explain what happens if the number of electrons in an atom changes. It is 1 of 3 in the series titled "Ions."

Study chemical bonding in chemistry including atoms, valence electrons, ionic and covalent bonding, and how molecules are formed on this site!

This lesson will explain that neutrons are particles in the nucleus that have no charge and a mass of one amu. It is 2 of 3 in the series titled "Subatomic Particles: The Neutron."

A very lengthy page from friesian.com discussing Bohr's theory of electronic energy levels and the explanation of commonly observed atomic emission line spectra. The concept of a photon and Einstein's observation of the photoelectric...

A very lengthy page from friesian.com discussing Bohr's theory of electronic energy levels and the explanation of commonly observed atomic emission line spectra. The concept of a photon and Einstein's observation of the photoelectric...

A very lengthy page from friesian.com discussing Bohr's theory of electronic energy levels and the explanation of commonly observed atomic emission line spectra. The concept of a photon and Einstein's observation of the photoelectric...

A very lengthy page from friesian.com discussing Bohr's theory of electronic energy levels and the explanation of commonly observed atomic emission line spectra. The concept of a photon and Einstein's observation of the photoelectric...

A very lengthy page from friesian.com discussing Bohr's theory of electronic energy levels and the explanation of commonly observed atomic emission line spectra. The concept of a photon and Einstein's observation of the photoelectric...

A very lengthy page from friesian.com discussing Bohr's theory of electronic energy levels and the explanation of commonly observed atomic emission line spectra. The concept of a photon and Einstein's observation of the photoelectric...

A very lengthy page from friesian.com discussing Bohr's theory of electronic energy levels and the explanation of commonly observed atomic emission line spectra. The concept of a photon and Einstein's observation of the photoelectric...

A very lengthy page from friesian.com discussing Bohr's theory of electronic energy levels and the explanation of commonly observed atomic emission line spectra. The concept of a photon and Einstein's observation of the photoelectric...

From the Brockport High School Physics Labs web pages. Includes an excellent graphic depicting the energy levels of a hydrogen atoms and portraying the electron level transitions for the Lyman, Balmer, and Paschen series. Includes both...

Brief explanation from Frostburg State University of valence bond theory and an explanation of what chemical situation creates a valence bond between two atoms.

This interactive activity from ChemThink takes a closer look at a covalent bond: how it is formed and how the sharing of two electrons can keep atoms together.

Water is both essential and unique. Many of its particular qualities stem from the fact that it consists of two hydrogen atoms and one oxygen, therefore creating an unequal sharing of electrons. From fish in frozen lakes to ice floating...

Explore molecule shapes by building molecules in 3D. How does molecule shape change with different numbers of bonds and electron pairs? Find out by adding single, double or triple bonds and lone pairs to the central atom. Then, compare...

Advanced chapter of the book "The Molecular Biology of the Cell" describes and provides illustrations of our most current understanding of the chemical makeup of cells and their components. Explains in detail how electron activity keeps...

An electron traveling through the wires and loads of the external circuit encounters resistance. In this tutorial, the concept of resistance is introduced. For an electron, the journey from terminal to terminal is not a direct route....

How Bohr's model of hydrogen explains atomic emission spectra.

Activity 1 in this module: What is the effect of changing the composition of an atom? Since all atoms contain protons, neutrons, and electrons, what makes one element different from another is examined.