<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (August 2015) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (August 2015) (Learn how and when to remove this template message) </Td> </Tr> <P> In chemistry, a synthetic element is a chemical element that does not occur naturally on Earth, and can only be created artificially . So far, 24 synthetic elements have been created (those with atomic numbers 95--118). All are unstable, decaying with half - lives ranging from 15.6 million years to a few hundred microseconds . </P> <P> Seven other elements were first created artificially and thus considered synthetic, but later discovered to exist naturally (in trace quantities) as well; among them plutonium--first synthesized in 1940--the one best known to laypeople, because of its use in atomic bombs and nuclear reactors . </P>

How many artificial elements are in the periodic table