Radioactive Elements Objective To learn about the radioactivity in elements Radioactivity is the process by which an unstable atomic nucleus will lose energy through the emitting of particles or electromagnetic waves. These emitted particles or electromagnetic waves are what are known as radiation. These exhibiting radioactivity are radioactive elements. The surrounding layers of an atom are built from negatively charged particles we know as electrons which revolve around a heavy positively charged nucleus. The nucleus is made of protons which carry a positive electrical charge and neutrons which carry new charge. The nucleus is considered stable once the forces of attraction and repulsion between its particles are balanced. When the number of particles in the nucleus is more sizable, as it is in atoms with higher atomic numbers, the nucleus will be unstable. The atomic number is the number of protons in the nucleus. There is a correlation between radioactivity and the atomic number of an element. Every element with an atomic number greater than that of lead 82 is radioactive. An unstable nucleus will attempt stability by undergoing the process of radioactive decay. Most naturally, occurring radioactive elements will emit either alpha particles or beta particles during this process. However, the emission of these particles is often accompanied by the emission of gamma rays. Elements such as radium will emit all three types of radiation. In alpha radiation, an alpha particle comprised of two protons and two neutrons will be released. During alpha decay, the mass of the nucleus will decrease by 4 and the atomic number of the atom will decrease by 2. Ameritradem 241 for example, will undergo alpha decay and form neptonium 237. During beta decay, an unstable nucleus will emit an energetic electron with a relatively small mass and an anti-neutrino with little mass. During this decay, a neutron will be converted into a proton. They are increasing the atomic number by 1, while leaving the mass number unchanged. Consider an atom of carbon with six protons. It will undergo beta decay and become an atom of nitrogen with seven protons. Following alpha or beta decay, the resulting dot-on nucleus will be in an excited state and contain high energy. This excited nucleus will emit short wavelength gamma rays. During gamma radiation, neither the atomic number nor its mass will be changed. Kobalt 60 Zinc 65 CCM 137 and radium 226 are some of the elements that will undergo gamma emission. Radical chemical elements such as uranium, radium, thorium and polonium are naturally radioactive. Summary Radioactivity is the process by which an unstable atomic nucleus loses energy through the emission of particles or electromagnetic waves. The occurring radioactive elements emit either alpha particles or beta particles.