Atomic Structure

The atom consists of various amounts of protons, neutrons, and electrons.  The nucleus of the atom contains the neutrons and protons.

For many years the atom was considered to be the smallest part of a substance.  By the end of the 19th century it appeared that the atom could be broken into smaller parts. These smaller parts are called subatomic particles.

Our concept of the atomic structure keeps changing as more is learned about the atom.