How Atoms Work

The Structure of the Atom: Early 20th-Century Science

To know the structure of the atom, we must know the following:

  • What are the parts of the atom?
  • How are these parts arranged?

Near the end of the 19th century, the atom was thought to be nothing more than a tiny indivisible sphere (Dalton's view). However, a series of discoveries in the fields of chemistry, electricity and magnetism, radioactivity, and quantum mechanics in the late 19th and early 20th centuries changed all of that. Here is what these fields contributed:


  • The parts of the atom: chemistry and electromagnetism ---> electron (first subatomic particle) radioactivity ---> nucleus proton neutron
  • How the atom is arranged - quantum mechanics puts it all together: atomic spectra ---> Bohr model of the atom wave-particle duality ---> Quantum model of the atom