Atomic number 100
Fermium
Actinide
No photo: here’s why
Fermium is a synthetic element made only in vanishingly small, intensely radioactive amounts - its atoms decay so quickly that no piece big enough to see or photograph has ever existed.
Quick facts
- Atomic mass
- 257.00
- Group
- –
- Period
- 7
- State (STP)
- solid
- Electronegativity
- 1.30
- Common ox. states
- +2, +3
Properties
[Rn] 5f¹² 7s²
- Ionization energy
- 627.0 kJ/mol
- Electron affinity
- –
- Melting point
- 1800.00 K (1526.8 °C)
- Boiling point
- –
How dangerous is it?
This element is made only a handful of atoms at a time and vanishes quickly, so it never builds up anywhere outside a lab.
- RadioactiveImmediate and cumulative
Its atoms are extremely short lived and intensely radioactive, decaying almost as fast as they are made. (barely exists outside a lab, and only as single atoms or smaller traces)
Created and measured in trace amounts inside shielded equipment at a few research labs.
How it bonds· family overview
Fermium (Fm) is an actinide. Like the lanthanides it tends toward a +3 oxidation state, but the early actinides (Th–Am) routinely access +4, +5, +6, even +7 because the 5f electrons are easier to ionize. Most actinides are radioactive; their "bonding" in school is read off the periodic table, not measured in lab.
