Radioactive decay is the disintegration of the nuclei of atoms in a radioactive element. These disintegrations are usually accompanied by the release of pieces of the nucleus and sometimes by the release of energy in the form of gamma rays. As the nucleus of an atom releases these particles and energy, it changes into the nucleus of a different atom or a nuclide. These nuclides are decay products of the original element, sometimes called progeny or Radon Decay Products (RDPs) and are important in understanding the radioactive decay process. In many cases, members of the decay chain are far more radioactive than the original nuclide as in the radon decay process.