Protoactinium
Protoactinium, Pa, is a metallic element, found in the actinide
series of inner transition metals in
Group IIIa of the periodic table.
- Atomic Number : 91
- Relative Atomic Mass : 231.04
Discovery
Protoactinium was discovered by Soddy in 1917AD, and
independently by Hahn and Meitner at about the same time.
Protoactinium was isolated as the metal by von Grosse in 1935AD.
Occurrence
Protoactinium occurs in pitchblende.
Properties
Protoactinium is
- radioactive,
- is fissionable with low energy neutrons and
- forms a reverse pair with Thorium, Th, in the Periodic Table
(i.e. the atomic weight of protoactinium is less than that of thorium).
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Elements ....
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