Protactinium (Pa, Z = 91)
Actinide Bloc f Groupe 3 Période 7 Solide (CNTP)
Protactinium is a chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume +4 and even +2 or +3 states.
Découvreur : William Crookes
Propriétés physiques
- Masse atomique standard
- 231,0 u
- Densité
- 15,37 g/cm³
- Point de fusion
- 1 841,0 K
- Point d'ébullition
- 4 300,0 K
- Chaleur molaire
- —
- Électronégativité (Pauling)
- 1,500
- Affinité électronique
- 53,03 kJ/mol
- Énergies d'ionisation
- 568 kJ/mol
- Configuration électronique
- [Rn] 5f2 6d1 7s2
- Électrons par couche
- K : 2 · L : 8 · M : 18 · N : 32 · O : 20 · P : 9 · Q : 2
- Aspect
- bright, silvery metallic luster
Correspondance ANU historique / conjectural
Comptage de la Chimie Occulte (1908) : 4 227 ANU (atomes ultimes), soit N/18 = 234,83 — masse « noologique » à comparer à la masse standard 231,036 u et à l'isotope dominant 231Pa. Coefficient k(Z) = 0,882
Matériel historique et conjectural — voir la page Pont ANU ↔ Nucléides.
Isotopes (31)
| Nucléide | A | N | Masse (u) | Abondance (%) | Demi-vie | Spin | Parité | Magique |
|---|---|---|---|---|---|---|---|---|
| 211Pa | 211 | 120 | 211,023674 | — | 6 ms | 9/2 | ⁻ | — |
| 212Pa | 212 | 121 | 212,023185 | — | 5.8 ms | 3 | ⁺ | — |
| 213Pa | 213 | 122 | 213,021100 | — | 7.4 ms | 9/2 | ⁻ | — |
| 214Pa | 214 | 123 | 214,020891 | — | 17 ms | 7 | ⁺ | — |
| 215Pa | 215 | 124 | 215,019114 | — | 14 ms | 9/2 | ⁻ | — |
| 216Pa | 216 | 125 | 216,019135 | — | 105 ms | 5 | ⁺ | — |
| 217Pa | 217 | 126 | 217,018309 | — | 3.8 ms | 9/2 | ⁻ | N magique |
| 218Pa | 218 | 127 | 218,020021 | — | 108 µs | 8 | ⁻ | — |
| 219Pa | 219 | 128 | 219,019950 | — | 56 ns | 9/2 | ⁻ | — |
| 220Pa | 220 | 129 | 220,021770 | — | 0.85 µs | 1 | ⁻ | — |
| 221Pa | 221 | 130 | 221,021873 | — | 5.9 µs | 9/2 | ⁻ | — |
| 222Pa | 222 | 131 | 222,023687 | — | 3.8 ms | 1 | ⁻ | — |
| 223Pa | 223 | 132 | 223,023980 | — | 5.3 ms | 9/2 | ⁻ | — |
| 224Pa | 224 | 133 | 224,025617 | — | 844 ms | 5 | ⁻ | — |
| 225Pa | 225 | 134 | 225,026148 | — | 1.71 s | 5/2 | ⁻ | — |
| 226Pa | 226 | 135 | 226,027948 | — | 1.8 min | 1 | ⁻ | — |
| 227Pa | 227 | 136 | 227,028804 | — | 38.3 min | 5/2 | ⁻ | — |
| 228Pa | 228 | 137 | 228,031051 | — | 22 h | 3 | ⁺ | — |
| 229Pa | 229 | 138 | 229,032096 | — | 1.55 j | 5/2 | ⁺ | — |
| 230Pa | 230 | 139 | 230,034540 | — | 17.4 j | 2 | ⁻ | — |
| 231Pa | 231 | 140 | 231,035883 | 100,0000 | 32.65 ka | 3/2 | ⁻ | — |
| 232Pa | 232 | 141 | 232,038590 | — | 1.32 j | 2 | ⁻ | — |
| 233Pa | 233 | 142 | 233,040247 | — | 26.975 j | 3/2 | ⁻ | — |
| 234Pa | 234 | 143 | 234,043306 | — | 6.7 h | 4 | ⁺ | — |
| 235Pa | 235 | 144 | 235,045399 | — | 24.4 min | 3/2 | ⁻ | — |
| 236Pa | 236 | 145 | 236,048668 | — | 9.1 min | 1 | — | |
| 237Pa | 237 | 146 | 237,051023 | — | 8.7 min | 1/2 | ⁺ | — |
| 238Pa | 238 | 147 | 238,054637 | — | 2.28 min | 3 | ⁻ | — |
| 239Pa | 239 | 148 | 239,057260 | — | 1.8 h | 1/2 | ⁺ | — |
| 240Pa | 240 | 149 | 240,061203 | — | — | 3 | ⁺ | — |
| 241Pa | 241 | 150 | 241,064134 | — | — | 1/2 | ⁺ | — |
Liseré coloré en première colonne : vert = stable, jaune = demi-vie > 1 an, orange > 1 jour, rouge < 1 jour.