Américium (Am, Z = 95)
95
Am
243,000 u
Actinide Bloc f Groupe 3 Période 7 Solide (CNTP)
Americium is a radioactive transuranic chemical element with symbol Am and atomic number 95. This member of the actinide series is located in the periodic table under the lanthanide element europium, and thus by analogy was named after the Americas. Americium was first produced in 1944 by the group of Glenn T.Seaborg from Berkeley, California, at the metallurgical laboratory of University of Chicago.
Découvreur : Glenn T. Seaborg
Propriétés physiques
- Masse atomique standard
- 243,0 u
- Densité
- 12,00 g/cm³
- Point de fusion
- 1 449,0 K
- Point d'ébullition
- 2 880,0 K
- Chaleur molaire
- 62,70 J·mol⁻¹·K⁻¹
- Électronégativité (Pauling)
- 1,130
- Affinité électronique
- 9,930 kJ/mol
- Énergies d'ionisation
- 578 kJ/mol
- Configuration électronique
- [Rn] 5f7 7s2
- Électrons par couche
- K : 2 · L : 8 · M : 18 · N : 32 · O : 25 · P : 8 · Q : 2
- Aspect
- silvery white
Isotopes (27)
| Nucléide | A | N | Masse (u) | Abondance (%) | Demi-vie | Spin | Parité | Magique |
|---|---|---|---|---|---|---|---|---|
| 223Am | 223 | 128 | 223,045840 | — | 10 ms | 9/2 | ⁻ | — |
| 224Am | 224 | 129 | 224,046442 | — | — | — | — | |
| 225Am | 225 | 130 | 225,045508 | — | — | 9/2 | ⁻ | — |
| 226Am | 226 | 131 | 226,046130 | — | — | — | — | |
| 227Am | 227 | 132 | 227,045282 | — | — | 9/2 | ⁻ | — |
| 228Am | 228 | 133 | 228,046001 | — | — | — | — | |
| 229Am | 229 | 134 | 229,045283 | — | 1.8 s | 5/2 | ⁻ | — |
| 230Am | 230 | 135 | 230,046025 | — | 40 s | 1 | ⁻ | — |
| 231Am | 231 | 136 | 231,045529 | — | — | 5/2 | ⁻ | — |
| 232Am | 232 | 137 | 232,046613 | — | 1.31 min | 1 | ⁻ | — |
| 233Am | 233 | 138 | 233,046468 | — | 3.2 min | 5/2 | ⁻ | — |
| 234Am | 234 | 139 | 234,047731 | — | 2.32 min | 0 | ⁻ | — |
| 235Am | 235 | 140 | 235,047906 | — | 10.3 min | 5/2 | ⁻ | — |
| 236Am | 236 | 141 | 236,049427 | — | 3.6 min | 5 | ⁻ | — |
| 237Am | 237 | 142 | 237,049995 | — | 73.6 min | 5/2 | ⁻ | — |
| 238Am | 238 | 143 | 238,051983 | — | 98 min | 1 | ⁺ | — |
| 239Am | 239 | 144 | 239,053023 | — | 11.9 h | 5/2 | ⁻ | — |
| 240Am | 240 | 145 | 240,055298 | — | 50.8 h | 3 | ⁻ | — |
| 241Am | 241 | 146 | 241,056827 | — | 432.6 an | 5/2 | ⁻ | — |
| 242Am | 242 | 147 | 242,059547 | — | 16.02 h | 1 | ⁻ | — |
| 243Am | 243 | 148 | 243,061380 | — | 7.35 ka | 5/2 | ⁻ | — |
| 244Am | 244 | 149 | 244,064283 | — | 10.01 h | 6 | ⁻ | — |
| 245Am | 245 | 150 | 245,066453 | — | 2.05 h | 5/2 | ⁺ | — |
| 246Am | 246 | 151 | 246,069774 | — | 39 min | 7 | ⁻ | — |
| 247Am | 247 | 152 | 247,072092 | — | 23 min | 5/2 | — | |
| 248Am | 248 | 153 | 248,075752 | — | — | 3 | ⁺ | — |
| 249Am | 249 | 154 | 249,078480 | — | — | 5/2 | — |
Liseré coloré en première colonne : vert = stable, jaune = demi-vie > 1 an, orange > 1 jour, rouge < 1 jour.