The last actinide, with an electron configuration that broke the expected pattern.
- Atomic number
- 103
- Atomic mass
- [262] u
- Phase
- Solid
- Electron configuration
- [Rn] 5f¹⁴ 7s² 7p¹
- Melting point
- 1,900 K · 1,626.9 °C
- Boiling point
- —
- Density
- 15.6 g/cm³
- Electronegativity
- 1.3
- Period / Group
- 7 / —
- Discovery year
- 1961