Compare Uranium vs Protactinium
Comparing Uranium (U) and Protactinium (Pa). Atomic numbers 92 and 91 with atomic masses 238.029 u and 231.036 u, classified as actinide and actinide. Below: a side-by-side comparison of their physical, atomic, electron-configuration and historical properties, including density, melting and boiling points, ionization energies, oxidation states and discovery history.
Periodic properties of the elements
| Uranium | Protactinium | |
|---|---|---|
| Symbol | U | Pa |
| Atomic number | 92 | 91 |
| Group | 0 | 0 |
| Period | 7 | 7 |
| Block | f | f |
| Element category | Actinide | Actinide |
Physical properties
| Uranium | Protactinium | |
|---|---|---|
| Phase at STP | Solid | Solid |
| Density | 19.1 g/cm3 | 15.37 g/cm3 |
| Atomic weight | 238.029 u | 231.036 u |
| Melting point | 1405.3 K 1132.15 °C 2069.87 °F | 1841 K 1567.85 °C 2854.13 °F |
| Boiling point | 4404 K 4130.85 °C 7467.53 °F | 4300 K 4026.85 °C 7280.33 °F |
Atomic properties
| Uranium | Protactinium | |
|---|---|---|
| Electronegativity (Pauling Scale) | 1.38 | 1.5 |
| Electron affinity | 50.94 kJ/mol | 53.03 kJ/mol |
| Oxidation states | +1, +2, +3, +4, +5, +6 (an amphoteric oxide) | +2, +3, +4, +5 (a weakly basic oxide) |
| Ionization energies |
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Electron configuration
| Uranium | Protactinium | |
|---|---|---|
| Shorthand configuration | [Rn] 5f3 6d1 7s2 | [Rn] 5f2 6d1 7s2 |
| Full configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f3 6s2 6p6 6d1 7s2 | 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, 21, 9, 2 | 2, 8, 18, 32, 20, 9, 2 |
History
| Uranium | Protactinium | |
|---|---|---|
| Prediction | Dmitri Mendeleev | |
| Discovery | Martin Heinrich Klaproth (1789) | Oswald Helmuth Göhring, Kazimierz Fajans (1913) |
| First isolation | Eugène-Melchior Péligot (1841) | |
| Named by | Otto Hahn, Lise Meitner (1917) |