Radiation at the quantum level, its definition and features. At the quantum level, radiation is the propagation of energy, indivisible particles that we call quanta, then the interaction of this energy Formation: Matter consists of atoms and nuclei that have energy levels, if the nucleus/electron receives too much energy or changes its state, then it wants to get rid of this energy, and rejects it from itself in particles (photons..). What are the features?: ~Discreteness: energy in this case is emitted in clear portions, and not continuously, consider that the atom is like a seller in a store giving out goods in packages. ~Quantum transitions: actions with energy occur only when the system transitions to different states. ~Ionization: radiation quanta (not everything will be radiation!) have a lot of energy, they can knock an electron out of an atom.