Editing Period 5 element (section)

===Ruthenium===
{{main|Ruthenium}}

'''Ruthenium''' is a [[chemical element]] with symbol '''Ru''' and [[atomic number]] 44. It is a rare [[transition metal]] belonging to the [[platinum group]] of the [[periodic table]]. Like the other metals of the platinum group, ruthenium is inert to most chemicals. The [[Russia]]n scientist [[Karl Ernst Claus]] discovered the element in 1844 and named it after [[Ruthenia]], the Latin word for [[Etymology of Rus and derivatives|Rus']]. Ruthenium usually occurs as a minor component of [[platinum]] ores and its annual production is only about 12 [[tonne]]s worldwide. Most ruthenium is used for wear-resistant electrical contacts and the production of thick-film resistors. A minor application of ruthenium is its use in some platinum [[alloy]]s.