Respuesta :
A same chemical element with different masses. It is also unstable and can release tons of energy which would emit radiation.
Answer:
A radioactive isotope, also known as a radioisotope, radionuclide, or radioactive nuclide, is any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.
Explanation: