Editing Chemical element (section)

=== Chemical definitions ===

==== Robert Boyle ====
{{rewrite|section|date=March 2024}}
[[File:Portret van Robert Boyle, RP-P-OB-4578 (cropped).jpg|thumb|200x200px|Robert Boyle, {{circa|1740}}]]
[[File:Sceptical chymist 1661 Boyle Title page AQ18 (3).jpg|thumb|330x330px|Title page of ''The Sceptical Chymist,'' published in 1661]]

In 1661, in ''[[The Sceptical Chymist]]'', [[Robert Boyle]] proposed his theory of corpuscularism which favoured the analysis of matter as constituted of irreducible units of matter (atoms); and, choosing to side with neither Aristotle's view of the four elements nor [[Paracelsus]]' view of three fundamental elements, left open the question of the number of elements. Boyle argued against a pre-determined number of elements—directly against Paracelsus' three [[Principle (chemistry)|principles]] (sulfur, mercury, and salt), indirectly against the [[Classical element|"Aristotelian" elements]] (earth, water, air, and fire), for Boyle felt that the arguments against the former were at least as valid against the latter.
{{Blockquote|text=Much of what I am to deliver ... may be indifferently apply'd to the four Peripatetick Elements, and the three Chymical Principles ... the Chymical ''Hypothesis'' seeming to be much more countenanc'd by Experience then the other, it will be expedient to insist chiefly upon the disproving of that; especially since most of the Arguments that are imploy'd against it, may, by a little variation, be made ... at least as strongly against the less plausible, ''Aristotelian'' Doctrine.{{Sfn|Boyle|1661|p=36}}}}

Then Boyle stated his view in four propositions. In the first and second, he suggests that matter consists of particles, but that these particles may be difficult to separate. Boyle used the concept of "corpuscles"—or "atomes",{{Sfn|Boyle|1661|p=38}} as he also called them—to explain how a limited number of elements could combine into a vast number of compounds.

{{Blockquote|text='''Propos. I.''' ''... At the first Production of mixt Bodies, the Universal Matter whereof they ... consisted, was actually divided into little Particles.''{{Sfn|Boyle|1661|p=37}} ... The Generation ... and wasting of Bodies ... and ... the Chymical Resolutions of mixt Bodies, and ... Operations of ... Fires upon them ... manifest their consisting of parts very minute...  ''Epicurus'' ... as you well know, supposes ... all ... Bodies ... to be produc'd by ... Atomes, moving themselves to and fro ... in the ... Infinite ''Vacuum''.{{Sfn|Boyle|1661|pp=37–38}} ... '''Propos. II.''' ''... These minute Particles ... were ... associated into minute ... Clusters ... not easily dissipable into such Particles as compos'd them.''{{Sfn|Boyle|1661|pp=38–39}} ... If we assigne to the Corpuscles, whereof each Element consists, a peculiar size and shape ... such ... Corpuscles may be mingled in such various Proportions, and ... connected so many ... wayes, that an almost incredible number of ... Concretes may be compos'd of them.{{Sfn|Boyle|1661|p=42}}}}

Boyle explained that gold reacts with ''[[aqua regia]],'' and mercury with nitric acid, sulfuric acid, and sulfur to produce various "compounds", and that they could be recovered from those compounds, just as would be expected of elements. Yet, Boyle did not consider gold,{{Sfn|Boyle|1661|p=29}} mercury,{{Sfn|Boyle|1661|p=41}} or lead{{Sfn|Boyle|1661|p=29}} elements, but rather—together with wine{{Sfn|Boyle|1661|p=145}}—"perfectly mixt bodies". 
{{Blockquote|text=Quicksilver ... with ''Aqua fortis'' will be brought into a ... white Powder ... with Sulphur it will compose a blood-red ... Cinaber. And yet out of all these exotick Compounds, we may recover the very same running Mercury.{{Sfn|Boyle|1661|pp=40–41}} ... '''Propos. III.''' ''... From most of such mixt Bodies ... there may by the Help of the Fire, be actually obtain'd a determinate number (whether Three, Four or Five, or fewer or more) of Substances ...''
The Chymists are wont to call the Ingredients of mixt Bodies, ''Principles'', as the ''Aristotelians'' name them ''Elements''. ... ''Principles'' ... as not being compounded of any more primary Bodies: and ''Elements'', in regard that all mix'd Bodies are compounded of them.{{Sfn|Boyle|1661|p=46}}}}

Even though Boyle is primarily regarded as the first modern chemist, ''The Sceptical Chymist'' still contains old ideas about the elements, alien to a contemporary viewpoint. Sulfur, for example, is not only the familiar yellow non-metal but also an inflammable "spirit".{{Sfn|Boyle|1661|p=145}}

==== Isaac Watts ====
[[File:Portrait of Isaac Watts, D.D..jpg|thumb|216x216px|Portrait of Isaac Watts by John Shury, {{circa|1830}}]]
In 1724, in his book ''[[Logick]]'', the English minister and logician [[Isaac Watts]] enumerated the elements then recognised by chemists. Watts' list of elements included two of Paracelsus' ''principles'' (sulfur and salt) and two classical elements (earth and water) as well as "spirit". Watts did, however, note a lack of consensus among chemists.<ref>{{Cite book |last=Watts |first=Isaac |url=https://archive.org/details/logickorrightuse00wattuoft/page/13/mode/1up |title=Logick: Or, the right use of reason in the enquiry after truth, with a variety of rules to guard against error in the affairs of religion and human life, as well as in the sciences |publisher=Printed for John Clark and Richard Hett |year=1726 |pages=13–15 |orig-date=1724}}</ref>
{{Blockquote|text=Elements are such Substances as cannot be resolved, or reduced, into two or more Substances of different Kinds. ... Followers of Aristotle made Fire, Air, Earth and Water to be the four Elements, of which all earthly Things were compounded; and they suppos'd the Heavens to be a Quintessence, or fifth sort of Body, distinct from all these : But, since experimental Philosophy ... have been better understood, this Doctrine has been abundantly refuted. The Chymists make Spirit, Salt, Sulphur, Water and Earth to be their five Elements, because they can reduce all terrestrial Things to these five :.. tho' they are not all agreed.}}

==== Antoine Lavoisier, Jöns Jacob Berzelius, and Dmitri Mendeleev ====
[[File:Mendeleev's 1869 periodic table.svg|upright=1.35|thumb|[[Mendeleev]]'s 1869 periodic table: ''An experiment on a system of elements. Based on their atomic weights and chemical similarities.'']]The first modern list of elements was given in [[Antoine Lavoisier]]'s 1789 ''[[Traité Élémentaire de Chimie|Elements of Chemistry]]'', which contained 33 elements, including [[light]] and [[Caloric theory|caloric]].<ref>{{cite book|last=Lavoisier|first=A. L.|year=1790|title=Elements of chemistry translated by Robert Kerr|url=https://books.google.com/books?id=4BzAjCpEK4gC&pg=PA175|place=Edinburgh|pages=175–176|isbn=978-0-415-17914-0|access-date=24 August 2020|archive-date=14 April 2021|archive-url=https://web.archive.org/web/20210414100525/https://books.google.com/books?id=4BzAjCpEK4gC&pg=PA175|url-status=live}}</ref><ref>{{Cite book |last=Lavoisier |first=Antoine |author-link=Antoine Lavoisier |url=https://www.gutenberg.org/cache/epub/30775/pg30775-images.html#Page_175 |title=Elements of chemistry: In a new systematic order, containing all the modern discoveries: Illustrated with thirteen copperplates |publisher=William Creech |year=1790 |pages=175–176 |language=en |translator-last=Kerr |translator-first=Robert |orig-date=1789}}</ref> By 1818, [[Jöns Jacob Berzelius]] had determined atomic weights for 45 of the 49 then-accepted elements. [[Dmitri Mendeleev]] had 63 elements in his 1869 periodic table.
[[File:DIMendeleevCab.jpg|thumb|left|upright|Dmitri Mendeleev, 1897]]
From Boyle until the early 20th century, an element was defined as a pure substance that cannot be decomposed into any simpler substance and cannot be transformed into other elements by chemical processes. Elements at the time were generally distinguished by their atomic weights, a property measurable with fair accuracy by available analytical techniques.