element 118

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element 118

a transuranium element that occupies position 118 in the periodic table and one of the noble gases. Element 118 is a synthetic element, and in 1999, scientists at Lawrence Berkeley National Laboratory in Berkeley, Calif., announced the production of atoms of element 118 as a result of the bombardment of lead-208 with atoms of krypton-86. However, in 2002, this result was retracted after it was discovered that some of the data had been falsified. In 2006, scientists at the Joint Institute for Nuclear Research at Dubna, Russia, announced that element 118 had been made in 2002 and 2005 in a cyclotron by the nuclear reaction of calcium-48 at an energy of 245 million electron volts (MeV) with a californium-249 target, leading to the loss of three neutrons and one atom of element 118. Nearly a millisecond after creation, the element 118 nucleus decays into another transuranium element, element 116, by emitting an alpha particle (helium nucleus). No physical or chemical properties of element 118 can be directly determined since only three atoms of element 118 have been produced. It is likely that element 118 may be a gas at room temperature. Like radon, the chemistry of element 118 is expected to reflect its anticipated metalloid properties. Element 118 has been temporarily christened "ununoctium" (Uuo), which means "one-one-eight" in Latin

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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