Protactinium (Pa)
Protactinium is the chemical element with atomic number 91 and symbol Pa. It is a actinide in period 7, with a standard atomic weight of 231.04 u.
Faits essentiels
- Z
- 91
- Atomic weight
- 231.04 u
- Category
- actinide
- State at 298 K
- Solid
- Occurrence
- from decay, radioactive
- Discovered
- 1917
- CAS
- 7440-13-3
Propriétés mesurées
| Property | Value | Source |
|---|---|---|
| Electronegativity | 1.5 | National Center for Biotechnology Information (NIH) |
| Melting point | 1,845 K | National Center for Biotechnology Information (NIH) |
| Density stp | 15.37 g/cm³ | National Center for Biotechnology Information (NIH) |
| Atomic radius empirical | 243 pm | National Center for Biotechnology Information (NIH) |
| Ionization energy 1st | 568.3 kJ/mol | National Center for Biotechnology Information (NIH) |
Configuration électronique
- Noble gas notation
- [Rn] 5f² 6d¹ 7s²
- Full notation
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f² 6s² 6p⁶ 6d¹ 7s²
- Electrons per shell
- 2, 8, 18, 32, 20, 9, 2