Radioaktivity

Radioactivity is the phenomenon by which atomic nuclei are unstable and spontaneously disintegrate, emitting energy in the form of radiation. This process, known as radioactive decay, occurs when an atom has an imbalanced number of protons and neutrons in its nucleus, making it energetically favorable to transform into a more stable configuration. The emitted radiation can take several forms, including alpha particles, beta particles, and gamma rays. Alpha particles consist of two protons and two neutrons, essentially a helium nucleus, and are relatively large and easily stopped. Beta particles are energetic electrons or positrons emitted from the nucleus. Gamma rays are high-energy photons, similar to X-rays, and are highly penetrating.

The rate at which a radioactive substance decays is characterized by its half-life, which is the time it takes for half of the radioactive atoms in a sample to decay. Half-lives vary greatly, from fractions of a second to billions of years, depending on the specific isotope. Radioactivity was first discovered by Henri Becquerel in 1896 and was later extensively studied by Marie and Pierre Curie. The discovery and understanding of radioactivity have had profound impacts on science and technology, leading to applications in medicine, such as diagnostic imaging and cancer treatment, as well as in industry for sterilization and dating ancient artifacts. However, radioactivity also poses health risks due to the damaging effects of ionizing radiation on living tissues, necessitating careful handling and safety protocols in its study and application.