Ununseptium

From Wikipedia, the free encyclopedia

Jump to: navigation, search

117

ununhexium ← ununseptium → ununoctium

At
↑
Uus
↓
(Uhs)

Periodic Table - Extended Periodic Table

General

Name, Symbol, Number

ununseptium, Uus, 117

Chemical series

presumably halogens

Group, Period, Block

17, 7, p

Appearance

unknown,
probably dark metallic

Standard atomic weight

predicted, (310) g·mol⁻¹

Electron configuration

perhaps [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁵
(guess based on astatine)

Electrons per shell

2, 8, 18, 32, 32, 18, 7

Phase

presumably a solid

CAS registry number

87658-56-8

Selected isotopes

Main article: Isotopes of ununseptium
iso	NA	half-life	DM	DE (MeV)	DP

References

Ununseptium (IPA: /ˌjuːnʌnˈsɛptiəm/) is the temporary name of an undiscovered chemical element in the periodic table that has the temporary symbol Uus and has the atomic number 117. Ununseptium can be referred to as eka-astatine.

[edit] History

The name ununseptium is used as a placeholder, as in scientific articles about the search for element 117. Transuranic elements (those beyond uranium) are, except for microscopic quantities and except for Plutonium, always artificially produced, and usually end up being named for a scientist or the location of a laboratory that does work in atomic physics (see systematic element name for more information).

Ununseptium has not yet been discovered. 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).^[1] Ununseptium may show semimetal properties as well.^{[citation needed]}