According to the generally accepted physical model, the synthesis of the heavy elements may happen at a very high temperature in supernova explosions. In consequence of nuclear fusion, the supernova stars emit a very strong electromagnetic (EM) radiation, predominantly in the form of X-rays and gamma rays. The intensive EM radiation drastically decreases the masses of the exploding stars, directly causing mass defects of the nuclei. The general description of black body EM radiation is based on the famous Planck?s radiation theory, which supposes the existence of independent quantum oscillators inside the black body. In this paper, it is supposed that in exploding supernova stars, the EM radiating oscillators can be identified with the nascent heavy elements loosing their specific yields of their own rest masses in the radiation process. The final binding energy of the nuclei is additionally determined by strong neutrino radiation, which also follows the Maxwell-Boltzmann distribution in extremely high temperature. Extending Planck?s radiation law for discrete radiation energies, a very simple formula is obtained for the theoretical description of the measured neutral atomic masses.