Radioactive is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha decay, beta decay, and gamma decay, all of which involve emitting one or more particles or photons. Every atom seeks to be as stable as possible. In the case of radioactive decay, instability occurs when there is an imbalance in the number of protons and neutrons in the atomic nucleus. There is too much energy inside the nucleus to hold all the nucleons together. Radioactivity is when tiny particles in objects emit energy or smaller particles. The energy that is produced can result in cancer, severe environmental damage, or helpful technologies. There are different degrees of radioactivity, and other exposures increase the harm it can cause.
Radiation Examples are; heat from a stove burner, visible light from a candle, x-rays from an x-ray machine, alpha particles emitted from the radioactive decay of uranium, sound waves from your stereo.