Page 8 - Curriculum Visions Dynamic Book

Protactinium (Pa)
Element 91.A radioactive
chemical element (originally called protoactinium) in the actinide series in the Periodic Table. It is one of the rarest elements and one of the most expensive to obtain. It is extremely dangerous and can cause radiation damage similar to plutonium. Protactinium is a superconductor
at 1.4 degrees above absolute zero.
Discovery
It was identified first in 1913 by K. Fajans and O. H. Gohring who named it ‘brevium’. It was then identified again in 1917 by Otto Hahn and Lise Meitner in Germany (who named it protoactinoim) and by Frederick Soddy, John Cranston and Sir Alexander Fleck in England. However, it was only in 1934 that it
was isolated from other elements byAristidV.Grosse.
Technology
It is used to make uranium-233 for nuclear reactors. It has almost no other use because of its rarity and expensive refining.
Geology
It is found as a minor part of all uranium ores such as pitchblende (uranite, UO2) because it results from the decay of uranium-238.
Biology
It is not found in living things. However, because it is radioactive, it is harmful if people are exposed to it.
Key facts...
Name: protactinium
Symbol: Pa
Atomic number: 91
Atomic weight: 231
Position in Periodic Table: inner transition
metal; period 7 (actinide series)
State at room temperature: solid
Colour: silvery-metallic
Density of solid: 15.37 g/cc
Melting point: 1568°C
Boiling point: 4,000°C
Origin of name: from the Greek word protos,
meaning first
Shell pattern of electrons: 2–8–18–32–20–9–2
8