what type of energy is released when one element decays into other elements?

Answer 1

Gamma rays, heat and, in the case of a few highly-radioactive elements, light; they glow in the dark. Beta particles which are high-energy electrons. Their kinetic energy can be converted into light by a phosphor such as zinc sulphide, or if they enter a transparent medium with a high refractive index, they emit blue Cerenkov radiation. Radioactive materials are warmer than their surroundings because alpha particles, beta rays and neutrons are all fast-moving particles and when they are absorbed their kinetic energy is converted into heat. In a nuclear reactor the heat is used to raise steam which drives a turbine. In the thermionic generators used on deep space probes it is converted directly into about 200 watts or so of electricity.

Answer 2

Energy is released foten as gamma ray, particle radiations( alfa, beta), heat, sometimes X rays.