Periodic Table: New Elements Added

Wednesday, June 8, 2011

NEW YORK — Two new elements have been added to the periodic table. The elements were recognized by an international committee of chemists and physicists. They're called elements 114 and 116 for now — permanent names and symbols will be chosen later. Scientists make them in labs by smashing atoms of other elements together to create the new ones. In contrast to more familiar elements like carbon, gold and tin, the new ones are short-lived. Atoms of 114 disintegrate within a few seconds, while 116 disappears in just a fraction of a second, Moody said. Both elements were discovered by a collaboration of scientists from Livermore and Russia. They made them by smashing calcium ions into atoms of plutonium or another element, curium. The official recognition, announced last week, cites experiments done in 2004 and 2006.

In the periodic table, the number of an element refers to the number of protons in the nucleus of an individual atom. Leading the list is hydrogen (H) with one. Sodium (Na) has 11, Iron (Fe) has 26, and silver (Ag) has 47. In the past 250 years, new elements have been added to the table about once every 2½ years on average, said Paul Karol of Carnegie Mellon University. He chaired the committee that recognized the new elements. Despite the number 116, the new additions bring the total number of recognized elements to just 114. That's because elements 113 and 115 haven't been officially accepted yet.