Editing Lutetium (section)

===Physical properties===
A lutetium atom has 71 electrons, arranged in the [[electron configuration|configuration]] &#91;[[xenon|Xe]]&#93;&nbsp;4f<sup>14</sup>5d<sup>1</sup>6s<sup>2</sup>.<ref name="Cotton">{{Greenwood&Earnshaw|page=1223}}</ref> Lutetium is generally encountered in the +3 oxidation state, having lost its two outermost 6s and the single 5d-electron. The lutetium atom is the smallest among the lanthanide atoms, due to the [[lanthanide contraction]],<ref>{{Cotton&Wilkinson5th|pages=776, 955}}</ref> and as a result lutetium has the highest density, melting point, and hardness of the lanthanides.<ref name="Parker">{{cite book| last=Parker | first= Sybil P.| title =Dictionary of Scientific and Technical Terms| edition =3rd| location = New York| publisher = McGraw-Hill| date = 1984}}</ref> As lutetium's 4f orbitals are highly stabilized only the 5d and 6s orbitals are involved in chemical reactions and bonding;<ref name=jensenlaw>{{cite web|url=http://www.che.uc.edu/jensen/W.%20B.%20Jensen/Reprints/081.%20Periodic%20Table.pdf|last1=Jensen|first1=William B.|author-link=William B. Jensen|title=The Periodic Law and Table|date=2000|archive-url=https://web.archive.org/web/20201110113324/http://www.che.uc.edu/jensen/W.%20B.%20Jensen/Reprints/081.%20Periodic%20Table.pdf |access-date=10 December 2022|archive-date=2020-11-10 }}</ref><ref>{{cite journal | last1=Krinsky | first1=Jamin L. | last2=Minasian | first2=Stefan G. | last3=Arnold | first3=John | title=Covalent Lanthanide Chemistry Near the Limit of Weak Bonding: Observation of (CpSiMe<sub>3</sub>)<sub>3</sub>Ce−ECp* and a Comprehensive Density Functional Theory Analysis of Cp<sub>3</sub>Ln−ECp (E = Al, Ga) | journal=Inorganic Chemistry | publisher=American Chemical Society (ACS) | volume=50 | issue=1 | date=2010-12-08 | issn=0020-1669 | doi=10.1021/ic102028d | pages=345–357| pmid=21141834 }}</ref> thus it is characterized as a d-block rather than an f-block element,<ref name="Jensen2015">{{cite journal |last1=Jensen |first1=William B. |date=2015 |title=The positions of lanthanum (actinium) and lutetium (lawrencium) in the periodic table: an update |url=https://link.springer.com/article/10.1007/s10698-015-9216-1 |journal=Foundations of Chemistry |volume=17 |pages=23–31 |doi=10.1007/s10698-015-9216-1 |s2cid=98624395 |access-date=28 January 2021 |archive-date=30 January 2021 |archive-url=https://web.archive.org/web/20210130011116/https://link.springer.com/article/10.1007/s10698-015-9216-1 |url-status=live }}</ref> and on this basis some consider it not to be a lanthanide at all, but a [[transition metal]] like its lighter congeners [[scandium]] and [[yttrium]].<ref>{{cite web |url=https://www.webelements.com/ |title=WebElements |last=Winter |first=Mark |date=1993–2022 |publisher=The University of Sheffield and WebElements Ltd, UK |access-date=5 December 2022 }}</ref><ref>{{cite book |last=Cowan |first=Robert D. |date=1981 |title=The Theory of Atomic Structure and Spectra |publisher=University of California Press |page=598 |isbn=978-0-520-90615-0}}</ref>