There are 38 radioactive elements in the periodic table. These elements either have no stable naturally occurring isotopes or are entirely artificial, with all isotopes being radioactive
. Specifically, elements with atomic numbers greater than 83 (bismuth) are all radioactive, meaning all their isotopes are unstable and emit radiation. This includes elements like uranium, radium, polonium, and thorium, which are common naturally radioactive elements
. Elements with atomic numbers above 92 (uranium) do not exist naturally and are synthesized in laboratories, and they are also radioactive
. In summary:
- 38 elements are classified as radioactive.
- All elements with atomic number greater than 83 are radioactive.
- Some radioactive elements occur naturally (e.g., uranium, radium).
- Others are artificial and created in labs (e.g., elements beyond uranium)
Thus, about 38 elements on the periodic table are radioactive.
