Question

how the radioactive isotopes release energy?

Answer 1

Radioactive isotopes (also called radioisotopes) have unstable nuclei. These isotopes disintegrate to form atoms with stable nuclei by the release of subatomic particles and gamma rays (akin to X-rays). The radioactive elements are referred to as parents atoms; the atoms they disintegrate to form are called daughter products.

Some isotopes release an alpha particleduring nuclear disintegration; an alpha particle consists of two protons and two neutrons (equivalent to the nucleus of an atom of helium). Others release a beta particle, which is an electron, or negatively charged nuclear particle. Beta particles originate in the nucleus, presumably by breakdown of a neutron into its proton-electron components. Gamma rays are released during both types of radioactive decay.