First artificially produced element

Technetium was discovered in 1937 by Italian scientists Carlo Perrier and Emilio Segrè at the University of Palermo, Sicily. They isolated the element from a sample of molybdenum, which had been exposed to high levels of radiation in a cyclotron. Its most stable isotope, technetium-98 has a half-life of around 4.2 million years, meaning that any significant mineral deposits of technetium in Earth’s crust have long since radioactively decayed into ruthenium-98. This shiny grey metallic element was detected in the spectral lines of some stars in 1952, providing evidence that heavier elements were indeed produced in stars. With an atomic number of 43, technetium is the lightest element known with no stable isotopes.