Isotopes that emit both an alpha particle and an electromagnetic wave are undergoing a radioactive decay process known as alpha decay. During alpha decay, an unstable atomic nucleus releases an alpha particle, which is composed of two protons and two neutrons. The emission of an alpha particle leads to a change in the atomic number and mass number of the nucleus.
In addition to the emission of an alpha particle, some isotopes may also release electromagnetic radiation in the form of gamma rays. Gamma rays are high-energy photons, which are a type of electromagnetic wave. They have no charge or mass and are highly penetrating.
The emission of gamma rays accompanies alpha decay when the nucleus transitions to a lower energy state. This transition involves the release of excess energy in the form of electromagnetic radiation. Gamma rays have the highest frequency and energy within the electromagnetic spectrum.
To summarize, when an isotope undergoes alpha decay, it emits both an alpha particle (which consists of two protons and two neutrons) and electromagnetic radiation in the form of gamma rays (which are high-energy photons).