Radioactive isotopes, also called radioisotopes, are unstable forms of elements that decay over time, releasing radiation in the process. This happens because their nuclei have an imbalance of protons and neutrons, making them energetically unstable.

To reach a more stable state, these isotopes undergo radioactive decay, emitting particles and/or energy in the form of:

• Alpha particles (α) – 2 protons and 2 neutrons
• Beta particles (β) – electrons or positrons
• Gamma rays (γ) – high-energy electromagnetic radiation

This decay process occurs at a predictable rate, measured by the half-life, which is the time it takes for half of the isotope’s atoms to decay.

Radioactive isotopes are used in many fields:

• Medicine (e.g., cancer treatment, diagnostic imaging)
• Archaeology (e.g., carbon-14 dating)
• Nuclear power (e.g., uranium-235 for energy production)
• Scientific research (e.g., tracing chemical pathways)

While useful, radioisotopes must be handled carefully due to the potential health risks associated with radiation exposure.