Uranium, which contains 92 protons, is the heaviest element known to occur in nature. But researchers have synthesised a number of even heftier elements, with as many as 118 protons.
These extreme atoms are quite short-lived – many fall apart just milliseconds after they are created. But nuclear theorists suspect that a class of 'super-heavy' atoms, boasting the right combination of protons and neutrons, could have lifetimes of decades or longer (see Hunting the biggest atoms in the universe).
Elements in this so-called island of stability could act as powerful nuclear fuel for future fission-propelled space missions. They might also be exhibit useful new chemical properties. Element 114, for example, has shown hints that it behaves like a gas at room temperature even though it should be a member of the lead family on the periodic table.http://www.newscientist.com/article/dn18510-weight-scale-for-atoms-could-map-island-of-stability.html?DCMP=OTC-rss&nsref=online-news