Editing Flerovium (section)

===Pre-discovery===
In the late 1940s to early 1960s, the early days of making heavier and heavier [[transuranic element]]s, it was predicted that since such elements did not occur naturally, they would have shorter and shorter [[spontaneous fission]] half-lives, until they stopped existing altogether around element 108 (now called [[hassium]]). Initial work in synthesizing the heavier [[actinide]]s seemed to confirm this.<ref name="Sacks">{{cite news|last=Sacks|first=O.|date=8 February 2004|title=Greetings From the Island of Stability|newspaper=[[The New York Times]]}}</ref> But the [[nuclear shell model]], introduced in 1949 and extensively developed in the late 1960s by William Myers and [[Władysław Świątecki (physicist)|Władysław Świątecki]], stated that [[proton]]s and [[neutron]]s form shells within a nucleus, analogous to [[electron shell]]s. [[Noble gas]]es are [[reactivity (chemistry)|unreactive]] due to a full electron shell; similarly, it was theorized that elements with full nuclear shells – those having "[[magic number (physics)|magic]]" numbers of protons or neutrons – would be stabilized against [[radioactive decay|decay]]. A doubly magic [[isotope]], with magic numbers of both protons and neutrons, would be especially stabilized. Heiner Meldner calculated in 1965 that the next doubly magic isotope after [[lead-208|{{chem2|^{208}Pb}}]] was {{chem2|^{298}Fl}} with 114 protons and 184 neutrons, which would be the centre of an "[[island of stability]]".<ref name="Sacks" /><ref name="quest">{{cite journal|last1=Bemis|first1=C.E.|last2=Nix|first2=J.R.|date=1977|title=Superheavy elements - the quest in perspective|journal=Comments on Nuclear and Particle Physics|volume=7|issue=3|pages=65–78|url=http://inspirehep.net/record/1382449/files/v7-n3-p65.pdf|issn=0010-2709}}</ref> This island of stability, supposedly from [[copernicium]] (''Z''&nbsp;=&nbsp;112) to [[oganesson]] (''Z''&nbsp;=&nbsp;118), would come after a long "sea of instability" from [[mendelevium]] (''Z''&nbsp;=&nbsp;101) to [[roentgenium]] (''Z''&nbsp;=&nbsp;111),<ref name="Sacks" /> and the flerovium isotopes in it were speculated in 1966 to have half-lives over 10<sup>8</sup>&nbsp;years.<ref name="emsley">{{cite book|last=Emsley|first=John|title=Nature's Building Blocks: An A-Z Guide to the Elements|edition=New|date=2011|publisher=Oxford University Press|location=New York, NY|isbn=978-0-19-960563-7|page=580}}</ref> These early predictions fascinated researchers, and led to the first attempt to make flerovium, in 1968 with the reaction {{chem2|^{248}Cm(^{40}Ar,xn)}}. No flerovium atoms were detected; this was thought to be because the compound nucleus {{chem2|^{288}Fl}} only has 174 neutrons instead of the supposed magic 184, and this would have significant impact on the reaction [[cross section (physics)|cross section]] (yield) and half-lives of nuclei produced.<ref name="Transuraniumppl">{{cite book|last1=Hoffman|first1=D.C|last2=Ghiorso|first2=A.|last3=Seaborg|first3=G.T.|title=The Transuranium People: The Inside Story|publisher=Imperial College Press|date=2000|isbn=978-1-86094-087-3|bibcode=2000tpis.book.....H}}</ref><ref name="superlourds">{{cite journal|last1=Epherre|first1=M.|last2=Stephan|first2=C.|date=1975|title=Les éléments superlourds|language=fr|journal=Le Journal de Physique Colloques|volume=11|issue=36|pages=C5–159–164|url=https://core.ac.uk/download/pdf/46775464.pdf|doi=10.1051/jphyscol:1975541}}</ref> It was then 30 more years before flerovium was first made.<ref name="Sacks" /> Later work suggests the islands of stability around hassium and flerovium occur because these nuclei are respectively deformed and [[oblate spheroid|oblate]], which make them resistant to spontaneous fission, and that the true island of stability for spherical nuclei occurs at around [[unbibium]]-306 (122 protons, 184 neutrons).<ref name="Kratz">{{cite conference|last1=Kratz|first1=J. V.|date=5 September 2011|title=The Impact of Superheavy Elements on the Chemical and Physical Sciences|url=http://tan11.jinr.ru/pdf/06_Sep/S_1/02_Kratz.pdf|conference=4th International Conference on the Chemistry and Physics of the Transactinide Elements|access-date=27 August 2013}}</ref><!--we can move this last sentence down later when we discuss the island of stability in greater detail-->

In the 1970s and 1980s, theoretical studies debated whether element 114 would be a more volatile metal like lead, or an inert gas.<ref name="tanm">{{cite web |last1=Gäggeler |first1=H. W. |date=5–7 November 2007 |title=Gas Phase Chemistry of Superheavy Elements |url=http://lch.web.psi.ch/files/lectures/TexasA&M/TexasA&M.pdf |url-status=dead |archive-url=https://web.archive.org/web/20120220090755/http://lch.web.psi.ch/files/lectures/TexasA%26M/TexasA%26M.pdf |archive-date=20 February 2012 |access-date=10 August 2013 |publisher=[[Paul Scherrer Institute]] |df=dmy-all}}</ref>