What is ionizing electromagnetic radiation?
The Planck-Einstein relation explains and quantify the amount of energy carried by electromagnetic (EM”) radiations (see our article: What is light?). The energy difference between both ends of EM spectrum can be over 1020 times. Physicists found that part of the EM radiation carries sufficient energy to liberate or remove electron(s) from atoms and turn atoms into ions, i.e., ionizing an atom. This can happen to molecules as well. Gamma rays, X-rays, and the higher ultraviolet part of the EM spectrum are generally considered as ionizing EM radiation; the rest of EM radiations in the EM spectrum are considered as non-ionizing EM radiation.