Which is the only radioactive element which occurs naturally as a gas?
Naturally occurring radioactive material 1 NORM industrial activity or a type 2 NORM industrial activity. Naturally occurring radioactive material Naturally Occurring Radioactive Materials (NORM) and Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) consist of materials, usually industrial wastes or by-products enriched with radioactive elements found in the environment, such as uranium, thorium and potassium and any of their decay products, such as radium and radon. Natural radioactive elements are present in very low concentrations in Earth's crust, and are brought to the surface through human activities such as oil and gas exploration or mining, and through natural processes like leakage of radon gas to
Monoisotopic element primordially which are not monoisotopic because the naturally occurring nuclide is radioactive, and thus the element has no stable isotopes at all. For an element to be monoisotopic, it must have one stable nuclide. Non-mononuclidic elements are marked with an asterisk, and the long-lived primordial radioisotope given. In two notable cases (indium and rhenium), the highest abundance naturally occurring isotope is the mildly radioactive one, and in the case of europium, nearly half of it is. Monoisotopic element A monoisotopic element is one of 26 chemical elements which have only a single stable isotope (nuclide). A list is given in