Posted by: Glow-worm PJ30 JUN 2011
In June it was announced that two new elements had been verified, with atomic numbers 114 and 116. They were given the provisional names ununquadium, and ununhexium.
The first scientific discovery of an element occurred in 1649 when Hennig Brand discovered phosphorus. By 1869, a total of 63 elements had been isolated, and it was recognised that there were patterns in their properties. Classification schemes were attempted, culminating in the publication, independently of each other, of the first modern periodic tables by the Russian Dmitri Mendeleev and the German Julius Meyer in 1869 and 1870, respectively.
Both were constructed along similar lines, but the success of Mendeleev’s table was his decision to leave gaps for elements that had not been discovered, allowing him to predict their properties. He also reordered some elements according to their properties, rather than their accepted atomic weights of the time, which were subject to experimental inaccuracies.
There are 92 naturally occurring elements, the last of which, francium, was discovered in 1939. The final major changes in the table resulted from the work of Glenn Seaborg. Starting with plutonium in 1940, he discovered the elements from 94 to 102, and reconfigured the table by placing the actinide series beneath the lanthanides. In 1951 he was awarded the Nobel Prize for chemistry and, in 1997, element 106 was named seaborgium in his honour after much wrangling between the two major research centres responsible for synthesis of new elements, in California, and at Dubna, to the north of Moscow. Their relationship, from the so-called transfermium wars, dating from the 1960s, is said to have relaxed since the cold war ended, but the proposed names for the new elements 114 and 116, flerovium and muscovium, after a Russian scientist and its capital, suggest that old habits die hard.