Editing Tennessine (section)

===Atomic and physical===
Tennessine is expected to be a member of group 17 in the periodic table, below the five halogens; [[fluorine]], [[chlorine]], [[bromine]], [[iodine]], and [[astatine]], each of which has seven valence electrons with a configuration of {{Nowrap|''n''s<sup>2</sup>''n''p<sup>5</sup>}}.<ref>{{Cite book |title = The Sterling Dictionary Of Chemistry |url = https://books.google.com/books?id=SvSmSYC6lW0C |publisher = Sterling Publishers Pvt. Ltd|date = 1999-12-01 |isbn = 978-81-7359-123-5 |first = A. |last = Dhingra |page = 187 |access-date = 2015-07-23}}</ref>{{efn|The letter ''n'' stands for the number of the [[period (chemistry)|period]] (horizontal row in the periodic table) the element belongs to. The letters "s" and "p" denote the ''s'' and ''p'' [[atomic orbital]]s, and the subsequent superscript numbers denote the numbers of electrons in each. Hence the notation {{Nowrap|''n''s<sup>2</sup>''n''p<sup>5</sup>}} means that the valence shells of lighter group 17&nbsp;elements are composed of two ''s'' electrons and five ''p'' electrons, all located in the outermost electron energy level.}} For tennessine, being in the seventh [[period (chemistry)|period]] (row) of the periodic table, continuing the trend would predict a valence electron configuration of {{Nowrap|7s<sup>2</sup>7p<sup>5</sup>}},<ref name="Haire" /> and it would therefore be expected to behave similarly to the halogens in many respects that relate to this electronic state. However, going down group&nbsp;17, the metallicity of the elements increases; for example, iodine already exhibits a metallic luster in the solid state, and astatine is expected to be a metal.<ref name="Hermann">{{cite journal
|doi=10.1103/PhysRevLett.111.116404|title=Condensed Astatine: Monatomic and Metallic|year=2013|last1=Hermann|first1=A.|last2=Hoffmann|first2=R.|last3=Ashcroft|first3=N. W.|journal=Physical Review Letters|volume=111|issue=11|pages=116404-1–116404-5|bibcode=2013PhRvL.111k6404H|pmid=24074111}}</ref> As such, an extrapolation based on periodic trends would predict tennessine to be a rather volatile metal.<ref name="GSI">{{cite web |url=https://www.superheavies.de/english/research_program/highlights_element_117.htm |title=Research Program – Highlights |author=GSI |date=14 December 2015 |website=superheavies.de |publisher=GSI |access-date=9 November 2016 |quote=If this trend were followed, element 117 would likely be a rather volatile metal. Fully relativistic calculations agree with this expectation, however, they are in need of experimental confirmation. |archive-date=13 May 2020 |archive-url=https://web.archive.org/web/20200513125453/https://www.superheavies.de/english/research_program/highlights_element_117.htm |url-status=dead }}</ref>

[[File:Valence atomic energy levels for Cl, Br, I, At, and 117.svg|class=skin-invert-image|thumb|upright=2.0|Atomic energy levels of outermost ''s'', ''p'', and ''d'' electrons of chlorine (d orbitals not applicable), bromine, iodine, astatine, and tennessine|alt=Black-on-transparent graph, width greater than height, with the main part of the graph being filled with short horizontal stripes]]

Calculations have confirmed the accuracy of this simple extrapolation, although experimental verification of this is currently impossible as the half-lives of the known tennessine isotopes are too short.<ref name="GSI" /> Significant differences between tennessine and the previous halogens are likely to arise, largely due to [[spin–orbit interaction]]—the mutual interaction between the motion and [[Spin (physics)|spin]] of electrons. The spin–orbit interaction is especially strong for the superheavy elements because their electrons move faster—at velocities comparable to the [[speed of light]]—than those in lighter atoms.{{sfn|Thayer|2010|pp=63–64}} In tennessine atoms, this lowers the 7s and the 7p electron energy levels, stabilizing the corresponding electrons, although two of the 7p electron energy levels are more stabilized than the other four.<ref name="Faegri">{{cite journal | last1 = Fægri Jr. | first1 = K. | last2 = Saue | first2 = T. | doi = 10.1063/1.1385366 | title = Diatomic molecules between very heavy elements of group&nbsp;13 and group&nbsp;17: A study of relativistic effects on bonding | journal = The Journal of Chemical Physics | volume = 115 | issue = 6 | pages = 2456 | year = 2001|bibcode = 2001JChPh.115.2456F | doi-access = free }}</ref> The stabilization of the 7s electrons is called the [[inert pair effect]]; the effect that separates the 7p subshell into the more-stabilized and the less-stabilized parts is called subshell splitting. Computational chemists understand the split as a change of the second ([[azimuthal quantum number|azimuthal]]) [[quantum number]] ''l'' from 1 to 1/2 and 3/2 for the more-stabilized and less-stabilized parts of the 7p subshell, respectively.{{sfn|Thayer|2010|pp=63–67}}{{efn|The quantum number corresponds to the letter in the electron orbital name: 0 to ''s'', 1 to ''p'', 2 to ''d'', etc. See [[azimuthal quantum number]] for more information.}} For many theoretical purposes, the valence electron configuration may be represented to reflect the 7p subshell split as {{Nowrap|7s{{su|p=2|w=70%}}7p{{su|b=1/2|p=2|w=70%}}7p{{su|b=3/2|p=3|w=70%}}}}.<ref name="Haire" />

Differences for other electron levels also exist. For example, the 6d electron levels (also split in two, with four being 6d<sub>3/2</sub> and six being 6d<sub>5/2</sub>) are both raised, so they are close in energy to the 7s ones,<ref name="Faegri" /> although no 6d electron chemistry has ever been predicted for tennessine. The difference between the 7p<sub>1/2</sub> and 7p<sub>3/2</sub> levels is abnormally high; 9.8&nbsp;[[electronvolt|eV]].<ref name="Faegri" /> Astatine's 6p subshell split is only 3.8&nbsp;eV,<ref name="Faegri" /> and its 6p<sub>1/2</sub> chemistry has already been called "limited".{{sfn|Thayer|2010|p=79}} These effects cause tennessine's chemistry to differ from those of its upper neighbors (see [[#Chemical|below]]).

Tennessine's first [[ionization energy]]—the energy required to remove an electron from a neutral atom—is predicted to be 7.7&nbsp;eV, lower than those of the halogens, again following the trend.<ref name="Haire" /> Like its neighbors in the periodic table, tennessine is expected to have the lowest [[electron affinity]]—energy released when an electron is added to the atom—in its group; 2.6 or 1.8&nbsp;eV.<ref name="Haire" /> The electron of the hypothetical [[hydrogen-like atom|hydrogen-like]] tennessine atom—oxidized so it has only one electron, Ts<sup>116+</sup>—is predicted to move so quickly that its mass is 1.90 times that of a non-moving electron, a feature attributable to [[Relativistic quantum chemistry|relativistic effects]]. For comparison, the figure for hydrogen-like astatine is 1.27 and the figure for hydrogen-like iodine is 1.08.{{sfn|Thayer|2010|p=64}} Simple extrapolations of relativity laws indicate a contraction of [[atomic radius]].{{sfn|Thayer|2010|p=64}} Advanced calculations show that the radius of a tennessine atom that has formed one covalent bond would be 165&nbsp;[[picometer|pm]], while that of astatine would be 147&nbsp;pm.<ref>{{Cite journal | last1 = Pyykkö | first1 = P. | last2 = Atsumi | first2 = M. | doi = 10.1002/chem.200800987 | pmid = 19058281 | title = Molecular Single-Bond Covalent Radii for Elements 1-118 | journal = Chemistry: A European Journal | volume = 15 | issue = 1 | pages = 186–197 | date = 2008-12-22 }}</ref> With the seven outermost electrons removed, tennessine is finally smaller; 57&nbsp;pm<ref name="Haire" /> for tennessine and 61&nbsp;pm<ref name="India" /> for astatine.

The melting and boiling points of tennessine are not known; earlier papers predicted about 350–500&nbsp;°C and 550&nbsp;°C, respectively,<ref name="Haire" /> or 350–550&nbsp;°C and 610&nbsp;°C, respectively.<ref name="Seaborg">{{cite book |title=Modern alchemy |author-link=Glenn T. Seaborg |first=Glenn T. |last=Seaborg |date=1994 |isbn=978-981-02-1440-1 |publisher=World Scientific |page=172 }}</ref> These values exceed those of astatine and the lighter halogens, following [[periodic trends]]. A later paper predicts the boiling point of tennessine to be 345&nbsp;°C<ref>{{cite journal |journal=Journal of Radioanalytical and Nuclear Chemistry |volume=251 |issue=2 |date=2002 |pages=299–301 |title=Boiling points of the superheavy elements 117 and 118 |first=N. |last=Takahashi |doi=10.1023/A:1014880730282 |bibcode=2002JRNC..251..299T |s2cid=93096903 }}</ref> (that of astatine is estimated as 309&nbsp;°C,<ref>{{cite book |editor-last=Ullmann |editor-first=F. |title=Encyclopedia of industrial chemistry |date=2005 |publisher=Wiley-VCH |doi=10.1002/14356007.a22_499 |isbn=978-3-527-30673-2 |first1=H. |last1=Luig |first2=C. |last2=Keller |first3=W. |last3=Wolf |first4=J. |last4=Shani |first5=H. |last5=Miska |first6=A. |last6=Zyball |first7=A. |last7=Gervé |first8=A. T. |last8=Balaban |first9=A. M. |last9=Kellerer |first10=J. |last10=Griebel |chapter=Radionuclides |page=23 |display-authors=3 }}</ref> 337&nbsp;°C,<ref>{{cite book |last1=Punter |first1=J. |last2=Johnson |first2=R. |last3=Langfield |first3=S. |title=The essentials of GCSE OCR Additional science for specification B |date=2006 |publisher=Letts and Lonsdale |isbn=978-1-905129-73-7 |page=36 }}</ref> or 370&nbsp;°C,<ref>{{cite book |last1=Wiberg |first1=E. |last2=Wiberg |first2=N. |last3=Holleman |first3=A. F. |title=Inorganic chemistry |url=https://books.google.com/books?id=Mtth5g59dEIC |date=2001 |publisher=Academic Press |isbn=978-0-12-352651-9 |page=423 }}</ref> although experimental values of 230&nbsp;°C<ref name="boiling_point_chromatography">{{cite journal |title=Estimation of the chemical form and the boiling point of elementary astatine by radiogas-chromatography |last1=Otozai |first1=K. |last2=Takahashi |first2=N. |journal=Radiochimica Acta |volume=31 |pages=201‒203 |date=1982 |url=https://www.mendeley.com/research/estimation-chemical-form-boiling-point-elementary-astatine-radio-gas-chromatography/ |issue=3‒4 |doi=10.1524/ract.1982.31.34.201 |s2cid=100363889 }}</ref> and 411&nbsp;°C<ref name="India">{{cite book |first=B. K. |last=Sharma |title=Nuclear and radiation chemistry |url=https://books.google.com/books?id=L8mBZcaGUQAC&pg=PA147 |access-date=2012-11-09 |date=2001 |edition=7th |publisher=Krishna Prakashan Media |isbn=978-81-85842-63-9 |page=147 }}</ref> have been reported). The density of tennessine is expected to be between 7.1 and 7.3&nbsp;g/cm<sup>3</sup>.<ref name="B&K" />