Attribute | Fermium × | Protactinium × |
---|---|---|
Atomic mass (u) | 257.09511 | 231.03588 |
Standard state | Solid | Solid |
1↑Oxidation states |
|
|
Electron configuration | [Rn]5f¹²7s² | [Rn]7s²5f²6d¹ |
Atomic radius (van der waals) (pm) | - | 243 |
Electronegativity (pauling scale) | 1.3 | 1.5 |
Melting point (K) | 1800 | 1845 |
Ionization energy (eV) | 6.5 | 5.89 |
Density (g/cm³) | - | 15.37 |
Atomic number | 100 | 91 |
Group name | Actinide | Actinide |
Symbol | Fm | Pa |
Discovered (year) | 1952 | 1913 |