108
Hs
Hassium
277
Hassium (Hs)
Transition MetalGroup 8Period 7d-block-blockRadioactive
Hassium is a chemical element with symbol Hs and atomic number 108, named after the German state of Hesse. It is a synthetic element (an element that can be created in a laboratory but is not found in nature) and radioactive; the most stable known isotope, 269Hs, has a half-life of approximately 9.7 seconds, although an unconfirmed metastable state, 277mHs, may have a longer half-life of about 130 seconds. More than 100 atoms of hassium have been synthesized to date.
Latin name: Hassium
Atomic Number
108
Atomic Mass
277 g/mol
Phase (STP)
Solid (predicted)
Electron Config.
[Rn] 5f¹⁴ 6d⁶ 7s²
General
SymbolHs
Atomic Number108
Atomic Mass277 g/mol
CategoryTransition Metal
Group8
Period7
Blockd-block
Electron Configuration[Rn] 5f¹⁴ 6d⁶ 7s²
Valence Electrons8
Colourmetallic (predicted)
Physical Properties
Phase (STP)Solid (predicted)
Density41 (predicted)
Melting Point1260 (predicted)
Boiling PointUnknown
Atomic Properties
Atomic Radius237 pm
Electronegativity1.3 Pauling
Oxidation States+8
Ion ChargeHs8+
Nuclear & Hazards
RadioactiveYes
Half-life11 minutes (Hs-277)
Abundance
In Earth's Crust0%
Discovery & History
Discovery Year1984
Discovered ByGesellschaft für Schwerionenforschung (GSI), Darmstadt
Country of DiscoveryGermany
Isotopes of Hassium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Hs-269 | — | ~9.7 seconds | α |
| Hs-277 | — | ~11 minutes | α |