A team of Russian and American scientists has discovered a new, still nameless, element. The paper, “Synthesis of a new element with atomic number Z=117,” will appear in the journal Physical Review Letters and was reported on in the New York Times yesterday.
Six atoms of this new element were produced by smashing calcium and berkelium together in a particle accelerator. Once the experiment has been replicated and confirmed, the new element will receive its name. At the moment, it is being referred to as ununseptium, a reference to its atomic number, 117. An atomic number refers to the number of protons (subatomic, positively charged particles) in the nucleus of an atom; The number of neutrons can vary. Out of the six atoms created, five contained 176 neutrons, the remaining had 177.
Data from this experiment supports the hypothesis that newly created atoms will become heavier and heavier until they reach a more stable, longer-lived state. This "island of stability" is, and has not been, seen among many artificially created elements which have short, unstable life spans (high decay rates). Stable atomic nuclei occur when the outermost shells of protons and neutrons are filled. Some theories project the center of this "island of stability" to be at 184 neutrons and either 120 or 126 protons. This new element is one more step toward this island and, likely, one more square on the periodic table of the elements.
The NYT article: http://www.nytimes.com/2010/04/07/science/07element.html?src=mv