Superheavy Element 117 Points to Fabled “Island of Stability” on Periodic Table. Physicists have created one of the heaviest elements yet, an atom with 117 protons in its nucleus. This jumbo-sized atom sits on the outer reaches of the periodic table where bloated nuclei tend to become less and less stable.

Why are superheavy elements unstable?

Superheavy elements are those elements with a large number of protons in their nucleus. Elements with more than 92 protons are unstable; they decay to lighter nuclei with a characteristic half-life.

How long can a superheavy elements live?

These elements have half-lives that are comparable to the age of the Earth, which is about 4.5 billion years old. Since the 1940s, however, physicists have been able to produce unstable elements that decay to lighter elements on timescales that can range from thousands of years to tiny fractions of a second.