Lawrencium
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Lawrencium is an exclusively artificially produced chemical element with the element symbol Lr and atomic number 103 In the periodic table it is in the group of actinides (7th period, f - block) and is also among the transuranic elements. Lawrencium is a radioactive metal that but have not been shown as a metal due to the limited quantities available. It was discovered in 1961, when they bombarded californium with boron nuclei. This element was named after Ernest Lawrence. He is the inventor of the cyclotron, a particle accelerator which was an important prerequisite for the discovery of many transuranium elements. The name was finally confirmed in 1994 by the IUPAC.
History
Lawrencium was first produced in 1961 by American scientists Albert Ghiorso, Torbjørn Sikkeland, Almon E. Larsh and Robert M. Latimer by Californiumisotope bombarded with nuclei of boron atoms. On 14 February 1961 she announced the successful synthesis of the element.
Initially we chose as a symbol " Lw ". In 1963 it was changed from the IUAPC ( International Union of Pure and Applied Chemistry ) in " Lr ".
Properties
In the periodic table the Lawrencium is consistent with the atomic number 103 in the series of actinides and closes it. Its predecessor is the nobelium, the subsequent element is the rutherfordium, but which already belongs to the Transactinoiden and a d- element. Its analogue in the series of lanthanides is the lutetium, which closes off also.
Lawrencium is a radioactive and very short-lived metal. There are ten known isotopes whose half-lives from a few seconds up to 3.6 hours. About other properties of the element has no information because the short half-life makes empirical studies almost impossible.
Safety
Classifications according to the Hazardous Substances Ordinance are not available because they only include the chemical danger and play a very minor role compared to the risks based on the radioactivity. Even the latter applies only if there is a relevant material for this amount.