Pa
Protactinium (Atomic Number 91)
Category: actinide | Period 7, Group 3 | Block: f
Rare, toxic, highly radioactive actinide formed during uranium decay.
Atomic & Physical Constants
- Standard Atomic Weight:
- 231.035882 u
- Standard State Phase:
- Solid
- Electron Configuration:
- 2, 8, 18, 32, 20, 9, 2
- Electronegativity (Pauling):
- 1.5
- Melting Point:
- 1841 K
- Boiling Point:
- 4300 K
Historical Discovery & Real-World Applications
Industrial & Scientific Uses
Paleoceanography radiometric sediment dating
Discovery History
Discovered by William Crookes (1917).
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