Hassium - Periodic Table of Videos

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.^[1]
In the periodic table of the elements, it is a d-block transactinide element. It is a member of the 7th period and belongs to the group 8 elements. Chemistry experiments have confirmed that hassium behaves as the heavier homologue to osmium in group 8. The chemical properties of hassium are characterized only partly, but they compare well with the chemistry of the other group 8 elements. In bulk quantities, hassium is expected to be a silvery metal that reacts readily with oxygen in the air, forming a volatile tetroxide.
Hassium is not known to occur naturally on Earth; the half-lives of all its known isotopes are short enough that no primordial hassium would have survived to the present day. This does not rule out the possibility of unknown longer-lived isotopes or nuclear isomers existing, some of which could still exist in trace quantities today if they are long-lived enough. In the early 1960s, it was predicted that long-lived deformed isomers of hassium might occur naturally on Earth in trace quantities. This was theorized in order to explain the extreme radiation damage in some minerals that could not have been caused by any known natural radioisotopes, but could have been caused by superheavy elements.^[1]
In 1963, Soviet scientist Victor Cherdyntsev, who had previously claimed the existence of primordial curium-247,^[15] claimed to have discovered element 108 (specifically, the ²⁶⁷Hs isotope, which supposedly had a half life of 400 to 500 million years) in natural molybdenite and suggested the name sergenium (symbol Sg; at the time, this symbol had not yet been taken by seaborgium) for it, after the ancient city of Serik along the Silk Road in Kazakhstan where his molybdenite samples came from.^[1] His rationale for claiming that sergenium was the heavier homologue to osmium was that minerals supposedly containing sergenium formed volatile oxides when boiled in nitric acid, similarly to osmium. His findings were criticized by V. M. Kulakov on the grounds that some of the properties Cherdyntsev claimed sergenium had were inconsistent with the then-current nuclear physics.^[16]