Atomic number 99 · actinide · Atomic mass 252 u
| Atomic Number | 99 |
| Atomic Mass | 252.0000 u |
| Category | actinide / 锕系元素 |
| Group | — |
| Period | 7 |
| Block | F |
| Electron Configuration | [Rn] 5f¹¹ 7s² |
| Electronegativity (Pauling) | 1.3 |
| Phase at STP | Solid |
| Density | 8.84 g/cm³ |
| Year Discovered | 1952 |
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