   #copyright

Roentgenium

2007 Schools Wikipedia Selection. Related subjects: Chemical elements


              111           darmstadtium ← roentgenium → ununbium
              Au
             ↑
             Rg
             ↓
             (Uhu)

                                  Periodic Table - Extended Periodic Table

                                                                   General
                                 Name, Symbol, Number roentgenium, Rg, 111
                                         Chemical series transition metals
                                             Group, Period, Block 11, 7, d
                                    Appearance unknown, probably yellow or
                                                           orange metallic
                                                   Atomic mass (284) g/mol
                      Electron configuration perhaps [Rn] 5f^14 6d^10 7s^1
                                                     (guess based on gold)
                               Electrons per shell 2, 8, 18, 32, 32, 18, 1
                                                  Phase presumably a solid
                                            CAS registry number 54386-24-2
                                                                References

   Roentgenium ( IPA: /ˌrəʊntˈgɛniəm/) is a chemical element in the
   periodic table that has the symbol Rg and atomic number 111 making it
   one of the super-heavy atoms. It is a synthetic element whose
   longest-lived isotope has a mass of 280 and a half-life of 3.6 seconds.
   Due to its presence in Group 11 it is a transition metal and so
   probably would appear as a heavy, solid, shiny metal. Due to the inert
   pair effect, it should be colored like gold.

History

   It was first created at the Gesellschaft für Schwerionenforschung (GSI)
   in Darmstadt, Germany on December 8, 1994. Only three atoms of it were
   observed (all ^272Rg), by the fusion of bismuth-209 and nickel-64 in a
   linear accelerator. (Nickel was bombarded onto the bismuth target.)

   The name roentgenium was accepted as a permanent name on November 1,
   2004 in honour of Wilhelm Röntgen; before this date, the element was
   known under the temporary IUPAC systematic element name unununium (
   IPA: /ˌuːˌnuːˈnuːniəm/, symbol Uuu). Some research has referred to it
   as eka- gold.

   The official baptism took place at GSI, on Friday November 17, 2006, in
   presence of Annette Schavan, the Federal German Minister of Research.

Isotopes

   Three isotopes of roentgenium are known. The longest-lived of these is
   ^280Rg which decays through alpha decay and has a half-life of 3.6 s.
   The shortest-lived isotope is ^272Rg which decays through alpha decay
   and has a half life of 1.5 ms. The other known isotope, ^279Rg, decays
   through alpha decay and has a half-life of 170 ms.

Trivia

   The elements in Group 11 used to informally be called the coinage
   metals, due to their historical use in coins. It is unlikely that
   roentgenium can be used to make coins since all of its isotopes are
   radioactive with very short half-lives.

   Retrieved from " http://en.wikipedia.org/wiki/Roentgenium"
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   with only minor checks and changes (see www.wikipedia.org for details
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