Name: Protactinium
Symbol: Pa
Atomic Number: 91
Atomic Mass: 231.03587 amu
Melting Point: 1600.0 °C (1873.15 °K, 2912.0 °F)
Boiling Point: Unknown
Number of Protons/Electrons: 91
Number of Neutrons: 140
Crystal Structure: Orthorhombic
Density @ 293 K: 15.4 g/cm3
Color: Unknown
Atomic Structure
![[Bohr Model of Protactinium]](b0091.gif) |
Number of Energy Levels: 7 First Energy Level: 2 Second Energy Level: 8 Third Energy Level: 18 Fourth Energy Level: 32 Fifth Energy Level: 20 Sixth Energy Level: 9 Seventh Energy Level: 2 |
Isotopes
| Isotope | Half Life |
| Pa-230 | 17.4 days |
| Pa-231 | 32800.0 years |
| Pa-233 | 27.0 days |
| Pa-234 | 6.69 hours |
| Pa-234m | 1.17 minutes |
Facts
Date of Discovery: 1917Discoverer: Fredrich Soddy
Name Origin: From the Greek word protos (first)
Uses: No uses known
Obtained From: fission product of uranium, thorium, plutonium
Information provided by: http://www.chemicalelements.com