What is radioactivity?

What is radioactivity? The atoms making up matter are generally stable, but some of them are spontaneously transformed by emitting radiations which release energy. This is called radioactivity. Atoms: In nature, matter - whether water, gas, rocks, living beings - consists of molecules, which are combinations of atoms. Atoms include a positively charged nucleus, around which move negatively charged electrons. The atom is neutral. The nucleus of the atom includes positively charged protons as well …

…proton into a neutron, beta+ radioactivity, characterized by the emission of an anti-electron or positron e+. It only appears in artificial radioactive nuclei produced by nuclear reactions. Gamma radioactivity, unlike the other two, is not related to a transmutation of the nucleus. It results in the emission, by the nucleus, of an electromagnetic radiation, like visible light or X-rays, but more energetic. Gamma radioactivity can occur by itself or together with alpha or beta radioactivity.