THE 106th chemical element, and the last to lack a formal name, has been called "seaborgium" after Glenn Seaborg, one of the world's most famous chemists.
With the naming of what has been called element "one-hundred-and-six-ium", all the 109 substances that make up the visible universe are now fully classified and explored. Only the nature of "dark invisible matter", which fills most of the cosmos, remains unknown.
The honour to Professor Seaborg was announced by the American Chemical Society in San Diego. Prof Seaborg, 81, is famous for his wartime discovery of the element plutonium, which he prepared for use in the atomic bombs that destroyed Hiroshima and Nagasaki. The discovery won him a Nobel prize.
He was also the co-discoverer of nine other elements heavier than uranium. Uranium occurs naturally, but the 17 elements heavier than uranium are man-made.
The 109 elements are numbered according to the weight of their atoms. The lightest, hydrogen, has the "atomic number" of one, and uranium is 92. They are called "elements" because they cannot be broken down into other substances by any non-nuclear means.
