VOA常速英語:澳大利亞科學家確認117號元素
George Putic
May 07,2014
Most of the naturally-occurring elements have already been discovered, but that does not mean that new elements cannot be created - only that they are too unstable to exist for a long time. Australian scientists recently reported creation of a new, super-heavy element.
The first 98 elements on the Periodic Table occur naturally, although some of them only in traces.
The other 19 - created in sophisticated laboratories - are extremely unstable and last only moments before decaying to more stable elements.
This includes the newest element - successfully created in a German laboratory by a multinational team of scientists led by Australian researchers. It's been temporarily named ununseptium, and is 40 percent heavier than lead.
Professor David Hinde, of the Australian National University, says a beam of calcium-48 nuclei, coming from an accelerator, flies into a scattering chamber where it hits atoms of berkelium-249.
"Inside this chamber then we have the target that the beam strikes, and our two large detectors which allow us to investigate which are the most suitable reactions to form super-heavy elements," said Hinde.
Creation of new elements helps scientists better understand the chemistry and physics of atoms, but it may also lead to the discovery of new technologies.
"What we learn here we hope will have broader application in the future," said Hinde.
Russian scientists also reported the creation of ununseptium in 2010. But the international body that verifies new elements, the International Union of Pure and Applied Chemistry (IUPAC), requires at least two independent successful experiments to confirm their existence.
Evidence of the next element on the list - element 118 - has also been found so scientists wonder if they will be able to create even more new elements.
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