Ununseptium

From Wikipedia, the free encyclopedia

117 ununhexium ← ununseptium → ununoctium
At

Uus

(Uhs)
Periodic Table - Extended Periodic Table
General
Name, Symbol, Number ununseptium, Uus, 117
Element category Unknown
Group, Period, Block 17, 7, p
Appearance Unknown
Standard atomic weight Unknown g·mol−1
Electron configuration Unknown
Electrons per shell 2, 8, 18, 32, 32, 18, 7
Phase Unknown
CAS registry number 87658-56-8
References

Ununseptium (pronounced /ˌjuːnənˈsɛptiəm/ or /ˌʌnənˈsɛptiəm/) is the temporary name of an undiscovered chemical element in the periodic table that has the temporary symbol Uus and the atomic number 117. Its half-life presumably will be 3 nanoseconds[citation needed]. It is expected to decay by alpha decay to element 115.

Ununseptium

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Contents

Future experiments

Ununseptium has not yet been discovered. As of March 2008, no attempt to synthesize this element has been reported.

Theoretical calculations in a quantum tunneling model with mass estimates from a macroscopic-microscopic model predict the alpha-decay half-lives of isotopes of the element 117 (namely, 289-303117) to be around 0.1-40 ms.

Chemical properties

Certain chemical properties, such as bond lengths, are predicted to differ from what one would expect based on periodic trends from the lighter halogens (because of relativistic effects). Ununseptium may show semimetal properties as well.

Naming

The name ununseptium is a systematic element name, used as a placeholder until it is confirmed by other research groups and the IUPAC decides on a name. Usually, the name suggested by the discoverer(s) is chosen.

References

  1. ^ C. Samanta, P. Roy Chowdhury and D.N. Basu (2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nucl. Phys. A 789: 142–154. doi:10.1016/j.nuclphysa.2007.04.001. 
  2. ^ P. Roy Chowdhury, C. Samanta, and D. N. Basu (2008). "Search for long lived heaviest nuclei beyond the valley of stability". Phys. Rev. C 77: 044603. doi:10.1103/PhysRevC.77.044603. 
  3. ^ P. Roy Chowdhury, C. Samanta, and D. N. Basu (2008). "Nuclear half-lives for α -radioactivity of elements with 100 < Z < 130". At. Data & Nucl. Data Tables. 
  4. ^ Trond Saue. "Principles and Applications of Relativistic Molecular Calculations"., page 76