WebElements Periodic Table » Protactinium (original) (raw)
Protactinium - 91Pa: the essentials
Name: protactinium
Symbol: Pa
Atomic number: 91
Relative atomic mass (_A_r): 231.03588 (2)
Standard state: solid at 298 K
Appearance: silvery metallic
Classification: Metallic
Group name: Actinoid
Period in periodic table: 7 (actinoid)
Shell structure: 2.8.18.32.20.9.2
CAS Registry: 7440-13-3
Protactinium atoms have 91 electrons and the shell structure is 2.8.18.32.20.9.2. The ground state electronic configuration of neutral protactinium is [Rn].5f2.6d1.7s2 and the term symbol of protactinium is 4K11/2.
Protactinium: description
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Protactinium has a bright metallic lustre which it retains for some time in air. The element is superconductive below 1.4 K. The element is a dangerous toxic material and requires precautions similar to those used when handling plutonium. Protactinium is one of the rarest and most expensive naturally occurring elements. The element is an α-emitter and is a radiological hazard similar to polonium. Protactinium is a highly toxic and radioactive rare earth metal that requires special handling. It is found in pitchblende and ores form Zaire and is one of the rarest and most expensive naturally occurring elements.
This sample of uraninite contains some about 10-6 grammes of actinium at any one time. Image adapted with permission from Prof James Marshall's (U. North Texas, USA) Walking Tour of the elements CD.
Protactinium: binary compounds
Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of protactinium where known.
Protactinium: compound properties
Bond strengths; lattice energies of protactinium halides, hydrides, oxides (where known); and reduction potentials where known.
Protactinium: history
Protactinium was discovered by Otto Hahn, Lise Meitner, Frederick Soddy, John Cranston in 1913 at Germany, England. Origin of name: from the Greek word "protos" meaning "first".
Protactinium: isolation
Isolation: coming soon!