| # | Symbol | Name | Atomic Mass | Category |
|---|---|---|---|---|
| 89 | Ac | Actinium | 227 | Actinides |
| 90 | Th | Thorium | 232.038 | Actinides |
| 91 | Pa | Protactinium | 231.036 | Actinides |
| 92 | U | Uranium | 238.029 | Actinides |
| 93 | Np | Neptunium | 237 | Actinides |
| 94 | Pu | Plutonium | 244 | Actinides |
| 95 | Am | Americium | 243 | Actinides |
| 96 | Cm | Curium | 247 | Actinides |
| 97 | Bk | Berkelium | 247 | Actinides |
| 98 | Cf | Californium | 251 | Actinides |
| 99 | Es | Einsteinium | 252 | Actinides |
| 100 | Fm | Fermium | 257 | Actinides |
| 101 | Md | Mendelevium | 258 | Actinides |
| 102 | No | Nobelium | 259 | Actinides |
| 103 | Lr | Lawrencium | 262 | Actinides |
15 elements