Neptunium (Np, Z = 93)
93
Np
237,000 u
Actinide Bloc f Groupe 3 Période 7 Solide (CNTP)
Neptunium is a chemical element with symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus.
Découvreur : Edwin McMillan
Propriétés physiques
- Masse atomique standard
- 237,0 u
- Densité
- 20,45 g/cm³
- Point de fusion
- 912,0 K
- Point d'ébullition
- 4 447,0 K
- Chaleur molaire
- 29,46 J·mol⁻¹·K⁻¹
- Électronégativité (Pauling)
- 1,360
- Affinité électronique
- 45,85 kJ/mol
- Énergies d'ionisation
- 605 kJ/mol
- Configuration électronique
- [Rn] 5f4 6d1 7s2
- Électrons par couche
- K : 2 · L : 8 · M : 18 · N : 32 · O : 22 · P : 9 · Q : 2
- Aspect
- silvery metallic
Isotopes (27)
| Nucléide | A | N | Masse (u) | Abondance (%) | Demi-vie | Spin | Parité | Magique |
|---|---|---|---|---|---|---|---|---|
| 219Np | 219 | 126 | 219,031602 | — | 570 µs | 9/2 | ⁻ | N magique |
| 220Np | 220 | 127 | 220,032716 | — | 29 ns | 1 | ⁻ | — |
| 221Np | 221 | 128 | 221,032110 | — | — | 9/2 | ⁻ | — |
| 222Np | 222 | 129 | 222,033575 | — | 480 ns | 1 | ⁻ | — |
| 223Np | 223 | 130 | 223,032913 | — | 2.5 µs | 9/2 | ⁻ | — |
| 224Np | 224 | 131 | 224,034388 | — | 48 µs | 2 | ⁻ | — |
| 225Np | 225 | 132 | 225,033943 | — | 6.5 ms | 9/2 | ⁻ | — |
| 226Np | 226 | 133 | 226,035230 | — | 35 ms | — | — | |
| 227Np | 227 | 134 | 227,034975 | — | 510 ms | 5/2 | ⁺ | — |
| 228Np | 228 | 135 | 228,036313 | — | 61.4 s | 4 | ⁺ | — |
| 229Np | 229 | 136 | 229,036287 | — | 4 min | 5/2 | ⁺ | — |
| 230Np | 230 | 137 | 230,037828 | — | 4.6 min | 4 | ⁺ | — |
| 231Np | 231 | 138 | 231,038244 | — | 48.8 min | 5/2 | ⁺ | — |
| 232Np | 232 | 139 | 232,040107 | — | 14.7 min | 5 | ⁻ | — |
| 233Np | 233 | 140 | 233,040739 | — | 36.2 min | 5/2 | ⁺ | — |
| 234Np | 234 | 141 | 234,042893 | — | 4.4 j | 0 | ⁺ | — |
| 235Np | 235 | 142 | 235,044062 | — | 396.1 j | 5/2 | ⁺ | — |
| 236Np | 236 | 143 | 236,046568 | — | 153 ka | 6 | ⁻ | — |
| 237Np | 237 | 144 | 237,048172 | — | 2.144 Ma | 5/2 | ⁺ | — |
| 238Np | 238 | 145 | 238,050945 | — | 2.099 j | 2 | ⁺ | — |
| 239Np | 239 | 146 | 239,052938 | — | 2.356 j | 5/2 | ⁺ | — |
| 240Np | 240 | 147 | 240,056164 | — | 61.9 min | 5 | ⁺ | — |
| 241Np | 241 | 148 | 241,058310 | — | 13.9 min | 5/2 | ⁺ | — |
| 242Np | 242 | 149 | 242,061640 | — | 2.2 min | 1 | ⁺ | — |
| 243Np | 243 | 150 | 243,064204 | — | 1.85 min | 5/2 | ⁺ | — |
| 244Np | 244 | 151 | 244,067891 | — | 2.29 min | 7 | ⁻ | — |
| 245Np | 245 | 152 | 245,070693 | — | — | 5/2 | ⁺ | — |
Liseré coloré en première colonne : vert = stable, jaune = demi-vie > 1 an, orange > 1 jour, rouge < 1 jour.