Attribute | Fermium × | Mendelevium × |
---|---|---|
Atomic mass (u) | 257.09511 | 258.09843 |
Standard state | Solid | Solid |
Oxidation states |
|
|
Electron configuration | [Rn]5f¹²7s² | [Rn]7s²5f¹³ |
Ionization energy (eV) | 6.5 | 6.58 |
Electronegativity (pauling scale) | 1.3 | 1.3 |
Melting point (K) | 1800 | 1100 |
Atomic number | 100 | 101 |
1↓Group name | Actinide | Actinide |
Discovered (year) | 1952 | 1955 |
Symbol | Fm | Md |