Protactinium is a chemical element in the periodic cairt that haes the seembol Pa, atomic nummer 91, an atomic mass 231.036.[2] It is a siller-coloured metal an ane o the actinides.[3] It readily reacts wi oxygen, watter vapor an inorganic acids. It forms sindry chemical compoonds whaur protactinium is uisually wi in the oxidation state +5, but it can assume +4 an e'en +3 or +2 states an aw. Concentrations o protactinium in the Yird's crust are teepically twa-three pairts ilka trillion, but micht rax tae twa-three pairts ilka million in some uraninite ore deposits. Acause o its scarcity, heich radioactivity an heich toxicity, thare arenae ony uises for protactinium ootwi scientific resairch the nou, an for this purpose, protactinium is maistly taen frae spent nuclear fuel.
The element wis first fund in 1913 bi Kazimierz Fajans an Oswald Helmuth Göhring an cried "brevium" acause o the short hauf-life o the speceefic isotope studied, i.e. protactinium-234m. A mair stable isotope o protactinium, 231Pa, wis diskivert in 1917/18 bi Lise Meitner in collaboration wi Otto Hahn, an thay chose the name protactinium.[4] The IUPAC chose the name "protactinium" in 1949 an confirmt Hahn an Meitner as diskiverers. The new name meant "(nuclear) precursor tae actinium",[5] an implied thit actinium is a product o radioactive decay o protactinium. John Arnold Cranston (working wi Frederick Soddy an Ada Hitchins) is credited wi diskiverin the maist stable isotope in 1915 an aw, but pit back his annooncement due tae bein cawed up for sairvice in the First Warld War.[6]
↑"Protactinium"(PDF). Human Health Fact Sheet. ANL (Argonne National Laboratory). November 2001. Retrieved 4 September 2023. The name comes from the Greek work protos (meaning first) and the element actinium, because protactinium is the precursor of actinium.
