* Uranium (U): A heavy, naturally occurring element commonly used in nuclear power.
* Plutonium (Pu): A synthetic element used in nuclear weapons and reactors.
* Radium (Ra): A naturally occurring element known for its radioactivity, used in medical treatments and luminous paint.
* Polonium (Po): A rare and highly radioactive element.
* Carbon-14 (C-14): A radioactive isotope of carbon used in radiocarbon dating.
* Iodine-131 (I-131): A radioactive isotope used in medical imaging and treatment.
* Cesium-137 (Cs-137): A radioactive isotope released during nuclear accidents and used in industrial applications.
These are just a few examples, and there are many other radioactive elements.
It's important to note that not all elements are radioactive. Only certain isotopes of some elements are radioactive. Isotopes are atoms of the same element that have different numbers of neutrons.
