francium, an alkali metal
No. It is not radioactive.
Tin is a naturally occurring metallic element. It is only created in supernova explosions. Radioactive tin can be created in nuclear reactors.
Technetium is a radioactive metallic element with no known taste or flavor. It is not naturally occurring on Earth and is primarily produced in nuclear reactors.
Carbon - 14 is the naturally produced right from Nitrogen being bombarded by cosmic rays in the upper atomosphere. Same way Uranium 235, polonium, radium etc are also available naturally. Several dozen radioactive elents at the Link.
Uranium and Plutonium
Thorium is an inner transition element, which means it is a metal.
It is radon that we see formed from the decay of naturally radioactive substances in the earth's crust.
First made in 1950 at the University of California. It is a radioactive metallic chemical element
NO!!! Because if it was, there would not be any silver jewellery/cutlery etc., about, because the radio-activity woulkd be dangerous.
Radium and polonium
Uranium is a natural chemical element, radioactive, dense, atomic number 92.Uranium is a solid metal.
It is radioactive decay.