91
Pa
Protactinium
Protactinium
Protactinium (Pa)
Actinides · Solid · Period 7 · Group 3
Element Properties
- Atomic Number
- 91
- Symbol
- Pa
- Atomic Mass
- 231.0359
- Category
- Actinides
- Standard State
- Solid
- Period
- 7
- Group
- 3
- Electronegativity
- 1.5
- Atomic Radius
- 243
- Ionization Energy
- 5.89
- Electron Affinity
- —
- Oxidation States
- +5, +4
- Melting Point
- 1845 K (1571.85 °C)
- Boiling Point
- —
- Density
- 15.37
- Electron Configuration
- [Rn]7s2 5f2 6d1
- Year Discovered
- 1913
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Frequently asked questions
What is the atomic number of Protactinium?
The atomic number of Protactinium is 91, which equals the number of protons in its nucleus.
What is the atomic mass of Protactinium?
The atomic mass of Protactinium is approximately 231.0359 u (one twelfth of the mass of a carbon-12 atom).
What is the electron configuration of Protactinium?
The electron configuration of Protactinium is [Rn]7s2 5f2 6d1.
Where is Protactinium in the periodic table?
Protactinium is located in period 7, group 3.
When was Protactinium discovered?
Protactinium was discovered in 1913.
Related elements
Same group
21
Sc
Scandium
44.956
39
Y
Yttrium
88.906
57
La
Lanthanum
138.905
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.908
60
Nd
Neodymium
144.24