Editing Octet rule (section)

== History ==
[[File:Newlands periodiska system 1866.png|thumb|upright=1.8|[[John Newlands (chemist)|Newlands]]' law of octaves]]

In 1864, the English chemist [[John Alexander Reina Newlands|John Newlands]] classified the sixty-two known elements into eight groups, based on their physical properties.<ref>See:
*{{cite journal|last1=Newlands|first1=John A. R.|title=On relations among the equivalents|journal=The Chemical News|date=7 February 1863|volume=7|pages=70–72|url=https://babel.hathitrust.org/cgi/pt?id=nyp.33433062748920;view=1up;seq=78}}
*{{cite journal|last1=Newlands|first1=John A. R.|title=On relations among the equivalents|journal=The Chemical News|date=20 August 1864|volume=10|pages=94–95|url=https://babel.hathitrust.org/cgi/pt?id=nyp.33433062749290;view=1up;seq=108}}
*{{cite journal|last1=Newlands|first1=John A. R.|title=On the law of octaves|journal=The Chemical News|date=18 August 1865|volume=12|page=83|url=https://babel.hathitrust.org/cgi/pt?id=nyp.33433062749274;view=1up;seq=97}}
*{{cite journal|last1=(Editorial staff)|title=Proceedings of Societies: Chemical Society: Thursday, March 1.|journal=The Chemical News|date=9 March 1866|volume=13|pages=113–114|url=https://babel.hathitrust.org/cgi/pt?id=nyp.33433062749266;view=1up;seq=121}}
*{{cite book|last1=Newlands|first1=John A.R.|title=On the Discovery of the Periodic Law and on Relations among the Atomic Weights|date=1884|publisher=London, England|location=E. & F.N. Spon|url=https://archive.org/stream/ondiscoveryperi02newlgoog#page/n4/mode/2up}}</ref><ref>in a letter published in ''Chemistry News'' in February 1863, according to the [http://www.nndb.com/people/480/000103171/ Notable Names Data Base]</ref><ref>[http://web.lemoyne.edu/~giunta/EA/NEWLANDSann.HTML Newlands on classification of elements]
</ref><ref>{{cite journal |last1=Ley |first1=Willy |title=For Your Information: The Delayed Discovery |journal=Galaxy Science Fiction |date=October 1966 |volume=25 |issue=1 |pages=116–127 |url=https://archive.org/stream/Galaxy_v25n01_1966-10#page/n115/mode/2up}}</ref>

In the late 19th century, it was known that coordination compounds (formerly called "molecular compounds") were formed by the combination of atoms or molecules in such a manner that the valencies of the atoms involved apparently became satisfied. In 1893, [[Alfred Werner]] showed that the number of atoms or groups associated with a central atom (the "[[coordination number]]") is often 4 or 6; other coordination numbers up to a maximum of 8 were known, but less frequent.<ref>See:
*  {{cite journal |last1=Werner |first1=Alfred |title=Beitrag zur Konstitution anorganischer Verbindungen |journal=Zeitschrift für anorganische und allgemeine Chemie |date=1893 |volume=3 |pages=267–330 |doi=10.1002/zaac.18930030136 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015072644209&view=1up&seq=271 |trans-title=Contribution to the constitution of inorganic compounds |language=de}}
*  English translation:  {{cite book |editor-last1=Werner |editor-first1=Alfred |editor-last2=Kauffman |editor-first2=G.B. |title=Classics in Coordination Chemistry, Part I: The selected papers of Alfred Werner |date=1968 |publisher=Dover Publications |location=New York City, New York, USA |pages=5–88}}</ref> In 1904, [[Richard Abegg]] was one of the first to extend the concept of [[coordination number]] to a concept of [[valence (chemistry)|valence]] in which he distinguished atoms as electron donors or acceptors, leading to positive and negative valence states that greatly resemble the modern concept of [[oxidation states]]. Abegg noted that the difference between the maximum positive and negative [[valence (chemistry)|valences]] of an [[chemical element|element]] under his model is frequently eight.<ref>{{cite journal
| doi = 10.1002/zaac.19040390125
| volume = 39
| issue = 1
| pages = 330–380
| last = Abegg
| first = R.
| title = Die Valenz und das periodische System. Versuch einer Theorie der Molekularverbindungen 
| trans-title = Valency and the periodic system. Attempt at a theory of molecular compounds
| journal = Zeitschrift für Anorganische Chemie
| year = 1904
| url = https://zenodo.org/record/1428102
}}</ref> In 1916, [[Gilbert N. Lewis]] referred to this insight as [[Abegg's rule]] and used it to help formulate his [[cubical atom]] model and the "rule of eight", which began to distinguish between [[valence (chemistry)|valence]] and [[valence electron]]s.<ref>{{cite journal
| doi = 10.1021/ja02261a002
| volume = 38
| issue = 4
| pages = 762–785
| last = Lewis
| first = Gilbert N.
| title = The Atom and the Molecule
| journal = Journal of the American Chemical Society
| year = 1916
| s2cid = 95865413
| url = https://zenodo.org/record/1429068
}}</ref>  In 1919, [[Irving Langmuir]] refined these concepts further and renamed them the "cubical octet atom" and "octet theory".<ref>{{cite journal
| doi = 10.1021/ja02227a002
| volume = 41
| issue = 6
| pages = 868–934
| last = Langmuir
| first = Irving
| title = The Arrangement of Electrons in Atoms and Molecules
| journal = Journal of the American Chemical Society
| year = 1919
| url = https://zenodo.org/record/1429026
}}</ref>  The "octet theory" evolved into what is now known as the "octet rule".

[[Walther Kossel]]<ref>{{cite journal |last1=Kossel |first1=W. |title=Über Molekülbildung als Frage des Atombaus |journal=Annalen der Physik |date=1916 |volume=354 |issue=3 |pages=229–362 |doi=10.1002/andp.19163540302 |bibcode=1916AnP...354..229K |url=https://babel.hathitrust.org/cgi/pt?id=uiug.30112053562358&view=1up&seq=245 |trans-title=On the formation of molecules as a question of atomic structure |language=de}}</ref> and [[Gilbert N. Lewis]] saw that noble gases did not have the tendency of taking part in chemical reactions under ordinary conditions. On the basis of this observation, they concluded that [[atom]]s of [[noble gas]]es are stable and on the basis of this conclusion they proposed a theory of [[valence (chemistry)|valency]] known as "electronic theory of valency" in 1916:

{{quote|''During the formation of a chemical bond, atoms combine together by gaining, losing or sharing electrons in such a way that they acquire nearest noble gas configuration.''<ref>{{cite web|url=http://osulibrary.oregonstate.edu/specialcollections/coll/pauling/bond/papers/corr216.3-lewispub-19160400.html |title=The Atom and the Molecule. April 1916. - Published Papers and Official Documents - Linus Pauling and The Nature of the Chemical Bond: A Documentary History |publisher=Osulibrary.oregonstate.edu |access-date=2014-01-03 |url-status=dead |archive-url=https://web.archive.org/web/20131125222947/http://osulibrary.oregonstate.edu/specialcollections/coll/pauling/bond/papers/corr216.3-lewispub-19160400.html |archive-date=November 25, 2013 }}</ref>}}