Final answer:
Alpha decay emits a helium-4 nucleus, beta decay emits electrons or positrons causing changes in atomic number but not mass number, and gamma decay emits gamma rays without altering the nucleus' atomic composition.
Step-by-step explanation:
Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation. There are three major radioactive decay processes that involve different types of emissions: alpha decay, beta decay, and gamma decay.
- Alpha decay occurs when a nucleus emits an alpha particle, effectively a helium-4 nucleus. This results in a decrease in mass and atomic numbers by 4 and 2, respectively.
- Beta decay involves the emission of beta particles (electrons or positrons). A neutron changes into a proton, or vice versa, leading to an increase or decrease in the atomic number by one, but no change in mass number.
- Gamma decay is the release of gamma rays from an excited nucleus. It involves no change in the atomic or mass numbers, but results in a lower energy state for the nucleus.
Different isotopes will undergo different types of decays based on the stability of their nucleus, these decay processes are described using nuclear symbols that reflect the changes in atomic and mass numbers of the elements. Understanding these decay processes helps in applications such as radiometric dating techniques and calculating half-life.