How does radioactive decay occur?

Radioactive decay occurs when an unstable nucleus emits radiation to become more stable.

Radioactive decay is a spontaneous process that occurs in unstable atomic nuclei. These nuclei contain too many or too few neutrons compared to the number of protons in the nucleus, making them unstable. The three types of radiation emitted during radioactive decay are alpha particles, beta particles, and gamma rays.

Alpha decay occurs when an unstable nucleus emits an alpha particle, which is a helium nucleus consisting of two protons and two neutrons. This results in the atomic number decreasing by two and the mass number decreasing by four.

Beta decay occurs when an unstable nucleus emits a beta particle, which is either an electron or a positron. In beta minus decay, a neutron in the nucleus decays into a proton, emitting an electron and an antineutrino. In beta plus decay, a proton in the nucleus decays into a neutron, emitting a positron and a neutrino.

Gamma decay occurs when an unstable nucleus releases energy in the form of gamma rays, which are high-energy photons. Gamma decay does not change the atomic number or mass number of the nucleus.

The rate of radioactive decay is measured by the half-life, which is the time it takes for half of the radioactive atoms in a sample to decay. The half-life is a characteristic property of each radioactive isotope and can range from fractions of a second to billions of years. Radioactive decay plays an important role in nuclear power, medical imaging, and carbon dating.