Introduction: If you've ever heard of the word "radioactivity", you probably think of explosions and of health problems brought about by contact with radioactive substances. But, how exactly do radioactive forms of elements like gold and iron go about giving off radioactive emissions? They release specific types of radioactive emissions through what is known as a nuclear decay. Nuclear decay refers a process in which a radioactive element undergoes change into a different form by giving off radioactive emissions, such that the nucleus of the radioactive element changes into a completely different element altogether. This is possible because the number of protons in the nucleus can change.

Among the types of radioactive decay include alpha decay (the release of helium-4), beta decay (the release of an electron), positron decay (the release of a positron, or a particle with the same mass and an opposite charge to that of an electron), and gamma decay (the release of gamma rays, usually in the form of energy). Based on their fundamental differences in terms of what they are, these radioactive emissions can lead to the formation of different elements, depending on what kind of radioactive decay a radioactive isotope undergoes.

Real-world applications of radioactive decay include the use of tracers in the medical field to trace a radioisotope as it travels through a person's body and the use of ionization radiation in the form of gamma or beta decay to slow the growth of food. Many of these advances in the modern-day world would not have been made without an understanding of the different types of radioactive decay necessary.