|
[[Image:Latorre01.jpg|thumb|250px|'''Vice Admiral Juan José Latorre''']]
{{merge|Timeline of chemical element discovery}}
'''Juan José Latorre Benavente''' ([[Santiago de Chile|Santiago]]; [[March 24]], [[1846]] - [[July 9]], [[1912]]) Chilean Vice Admiral, one of the principal actors of the [[War of the Pacific]], and hero of the [[Battle of Angamos]].
==Early life==
__NOTOC__ <!--move it way up-->
Son of Elías Latorre and of Nicomedia Benavente, the oldest of eight brothers. After the early death of his father, three of his younger brothers were taken by the paternal family in [[Peru]], where they were raised. Later on, one of the brothers participated also in the [[War of the Pacific]], but on the Peruvian side.
At the age of nine, in [[1855]], he won a scholarship to the Naval Academy. Appointed midshipman on [[July 15]], [[1861]]. He served on the ''Esmeralda'' during the [[Chincha Islands War]] and participated in the [[Battle of Papudo]], where the Spanish shooner ''Covadonga'' was captured, and in the [[Battle of Abtao]].
The story of the '''discoveries of the [[chemical element]]s''' is presented here in chronological order. The elements are listed generally in the order in which they were first isolated as the pure element, rather than as a compound (some such as boron were known to be elements decades before they could be isolated from their compounds). The first few predate any written record.
On [[February 12]], [[1873]] was promoted to first lieutenant, and given command of the ''Toltén'' first, and the ''Magallanes'' later. It was in this later ship that he was going to make his name as one of the ablest naval commanders of the coming war. During his patrols of the extreme southern region of Chile, he was involved in a diplomatic incident with [[Argentina]] and Britain, when he captured several foreign ships that were operating in the Chilean area with an Argentinian licence, chief among them the ''Jeanne Amelie'' and the ''Devonshire''. He was also faced with the mutiny of the city of [[Punta Arenas]], where he was able to rescue his old friend, governor [[Diego Dublé Almeida]].
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
== War of the Pacific years ==
<tr>
<td>[[Carbon]]</td>
<td>antiquity</td>
<td>Unknown</td>
</tr>
===Naval Battle de Chipana===
<tr>
While in command of the ''Magallanes'', he was the first to come face to face with the Peruvian navy at the [[Battle of Chipana|Naval Battle de Chipana]]. On [[April 12]], [[1879]], he crossed paths with the Peruvian ships ''Unión'' and ''Pilcomayo'', who tried to capture it. Outgunned, Latorre decided to escape. During the ensuing persecution, he noticed that the speed of the two Peruvian ships was greatly different, and that the ''Pilcomayo'' was falling considerably behind.
<td>[[Gold]]</td>
<td>antiquity</td>
<td>Unknown</td>
</tr>
Once the Peruvian ''Union'' was alone, he turned his ship around, and opened fire. The battle thus ensued. The Peruvian aim was disastrous, due to their lack of training, but the Chilean aim was only marginally better. At one point, the ''Unión'' started spewing white smoke from one of its sides. This led the Peruvian captain to think his ship had been seriously hit, and gave up the persecution, allowing the weaker ''Magallanes'' to escape unharmed. In fact the whole incident was caused by the overheating of one of the boilers.
<tr>
<td>[[Silver]]</td>
<td>antiquity</td>
<td>Unknown</td>
</tr>
===Second Naval Battle of Iquique===
<tr>
After the disastrous reduction of the Peruvian navy at the First [[Battle of Iquique|Naval Battle of Iquique]], presidente [[Mariano Ignacio Prado|Prado]] of Peru ordered Admiral [[Miguel Grau|Grau]] to harass the Chilean shipping lines and to try to disrupt their commerce. The Admiral, on the ''Huascar'', decided to go on a night raid to the port of [[Iquique]], to try and destroy the ''Abtao''. He arrived on the night of [[July 9]], and not finding his prey decided to go after the transport ship ''Matías Cousiño.''
Latorre, who was commanding the ''Magallanes'' decided to fend off the attack, in spite of the difference in strength of both ships (260 tons versus 1130). Admiral Grau tried to sink the smaller ship thrice, using his ram, but in spite of his ability the ''Magallanes'' was able to keep him at bay long enough for the ironclad ''Cochrane'' to show up, after which the ''Huascar'' decided to retreat back to [[Arica]].
<td>[[Copper]]</td>
<td>antiquity</td>
<td>Unknown</td>
</tr>
=== [[Battle of Angamos|Naval Battle of Angamos]] ===
<tr>
[[Image:Angamos.jpg|thumb|300px|[[Battle of Angamos|Naval Battle of Angamos]]]]
<td>[[Sulfur]]</td>
On [[September 6]], [[1879]] he is promoted to commander of the ironclad ''Cochrane'', the strongest unit of the Chilean fleet. His fame was such that he moved in with all his crew. His first mission was to eliminate the threat of the ''Huascar'', who was impeding alone any invasion of the Peruvian coastline.
<td>antiquity</td>
<td>Unknown</td>
</tr>
On the night of [[October 7]] he was informed that the ''Huascar'' had been seen near the port of Huasco and was moving north. A trap was then set. The Chilean fleet was divided into 2 groups. The first division was in charge of Commander [[Galvarino Riveros]] and made up of the ''Blanco Encalada'', ''Covadonga'' and the ''Matías Cousiño'' (the last one loaded with coal), who would try to follow Admiral Grau pushing him towards the second division that would be waiting further north. In the early hours of [[October 8]], the plan went into effect. When the ''Huascar'' and the ''Union'' saw the Chilean ships blocking their way south they decided to turn back north. A few hours later, they met the ''Cochrane'' who was waiting according to plan. Admiral Grau was forced to present battle, while the ''Union'' got away.
<tr>
<td>[[Tin]]</td>
<td>antiquity</td>
<td>Unknown</td>
</tr>
The ''Cochrane'' continued advancing over the ''Huascar'' without answering its fire until it was very close to the enemy, in order not to lose speed. When it finally attacked, the onslaught was ferocious. The second shot destroyed the command tower of the ''Huascar'', killing Admiral [[Miguel Grau Seminario|Grau]] and leaving the monitor without a rudder. The fight continued for another hour, but the arrival of the ''Blanco Encalada'' with the rest of the Chilean fleet made any resistance totally useless. The ''Huascar'' was captured and became a part of the Chilean fleet.
<tr>
<td>[[Lead]]</td>
<td>antiquity</td>
<td>Unknown</td>
</tr>
== Later years ==
<tr>
After returning to Chile, in [[1882]] he married Julia Moreno Zuleta, whom he met on one of the many parties given in his honor after the war. They had three children. On [[June 5]], [[1884]] he is promoted to Rear-Admiral. In [[1886]] he was appointed Commander General of the Navy. Presidente [[José Manuel Balmaceda]] sent him on an official mission to Europe to supervise the construction of new ships for the Chilean navy. While in [[England]], the [[Chilean Civil War]] broke out. He chose to remain loyal to president Balmaceda and was dismissed after the Congressional triumph. He remained in exile in Europe until [[1894]].
<td>[[Mercury (element)|Mercury]]</td>
<td>antiquity</td>
<td>Unknown</td>
</tr>
After his return, he was twice elected senator for the Balmacedista party ([[1894]]-[[1900]], [[1900]]-[[1906]]), and was reinstated in the navy. He was appointed member of the Council of State by president [[Federico Errázuriz Echaurren]] in [[1897]] and minister of foreign affairs in [[1898]]. A few years before his death he was promoted to Vice Admiral and was made a Commander of the French [[Legion of Honor]].
<tr>
<td>[[Iron]]</td>
<td>antiquity</td>
<td>Unknown</td>
</tr>
{{start box}}
</table>
{{s-off}}
{{succession box
| title=[[Ministry of Foreign Affairs of Chile#Ministers of Foreign Affairs and Cult|Minister of Foreign Affairs and Cult]]
| before=[[Raimundo Silva]]
| after=[[Ventura Blanco]]
| years='''1898-1899'''}}
{{s-mil}}
{{succession box
| title=[[Chilean Navy|Navy General Commander]]
| before=[[Domingo Toro]]
| after=[[Luis Uribe]]
| years='''1886-1887'''}}
{{end box}}
[[Category:1846 births|Latorre, Juan José]]
Although Aluminium ''may'' have been isolated in Roman times (see [[Aluminium#History]]), its isolation is usually credited to Hans Christian Ørsted in 1825, and is listed under that date.
[[Category:1912 deaths|Latorre, Juan José]]
[[Category:Chilean military personnel|Latorre, Juan José]]
<table border="1" cellspacing="0" cellpadding="2" width="75%">
[[Category:Chilean admirals|Latorre, Juan José]]
[[Category:People of the War of the Pacific|Latorre, Juan José]]
<tr>
<td>[[Arsenic]]</td>
<td>[[1250]]</td>
<td>[[Albertus Magnus]] is believed to have been the first to isolate the
element. </td>
</tr>
<tr>
<td>[[Antimony]]</td>
<td>[[1450]]</td>
<td>First described scientifically by [[Tholden]]</td>
</tr>
<tr>
<td>[[Bismuth]]</td>
<td>[[15th century]]?</td>
<td>May have been described in writings attributed to
[[Basil Valentinus]], definitively identified by [[Claude Geoffroy Junine]] in 1753</td>
</tr>
<tr>
<td>[[Zinc]]</td>
<td>[[1526]]</td>
<td>Identified as a unique metal by [[Paracelsus]]</td>
</tr>
<tr>
<td>[[Phosphorus]]</td>
<td>[[1669]]</td>
<td>[[Hening Brand]], later described by [[Robert Boyle]]</td>
</tr>
<tr>
<td>[[Cobalt]]</td>
<td>[[1732]]</td>
<td>[[Georg Brandt]]</td>
</tr>
</table>
Platinum had been noticed in South American gold ore since the [[16th century]]. A number of chemists worked on platinum in the [[18th century]]:
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Platinum]]</td>
<td>ca. [[1741]]</td>
<td>Discovered independently by [[Antonio de Ulloa]] (published 1748) and [[Charles Wood (scientist)|Charles Wood]].</td>
</tr>
<tr>
<td>[[Nickel]]</td>
<td>[[1751]]</td>
<td>[[Axel Fredrik Cronstedt]]</td>
</tr>
<tr>
<td>[[Magnesium]]</td>
<td>[[1755]]</td>
<td>[[Joseph Black]]</td>
</tr>
<tr>
<td>[[Hydrogen]]</td>
<td>[[1766]]</td>
<td>Isolated and described by [[Henry Cavendish]], named by [[Antoine Lavoisier]]</td>
</tr>
</table>
[[Joseph Priestley|Priestley]]'s work on atmospheric gases resulted
in his preparation of oxygen. As he was a believer in [[phlogiston theory|phlogiston]], he didn't realise that he had prepared a new
element, and thought that he had managed to prepare air free from
phlogiston ("de-phlogisticated air"). However, he ''was'' the
first to isolate oxygen, even if he didn't realise what he had:
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Oxygen]]</td>
<td>[[1771]]</td>
<td>[[Joseph Priestley]]</td>
</tr>
<tr>
<td>[[Nitrogen]]</td>
<td>[[1772]]</td>
<td> [[Daniel Rutherford]]</td>
</tr>
<tr>
<td>[[Chlorine]]</td>
<td>[[1774]]</td>
<td>[[Carl Wilhelm Scheele]]</td>
</tr>
<tr>
<td>[[Manganese]]</td>
<td>[[1774]]</td>
<td>[[Johan Gottlieb Gahn]]</td>
</tr>
<tr>
<td>[[Molybdenum]]</td>
<td>[[1778]]</td>
<td>[[Carl Wilhelm Scheele]]</td>
</tr>
<tr>
<td>[[Tellurium]]</td>
<td>[[1782]]</td>
<td>[[Franz-Joseph Müller von Reichenstein]]</td>
</tr>
<tr>
<td>[[Tungsten]]</td>
<td>[[1783]]</td>
<td>[[Juan José Elhuyar]] and [[Fausto Elhuyar]]</td>
</tr>
</table>
The recent discovery of the new planet [[Uranus (planet)|Uranus]] by [[William Herschel]] had caused a stir, so the newly discovered metallic
element was christened uranium in its honour.
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Uranium]]</td>
<td>[[1789]]</td>
<td>[[Martin Heinrich Klaproth]]</td>
</tr>
<tr>
<td>[[Zirconium]]</td>
<td>[[1789]]</td>
<td>[[Martin Heinrich Klaproth]]</td>
</tr>
<tr>
<td>[[Strontium]]</td>
<td>[[1793]]</td>
<td>[[Martin Heinrich Klaproth]]</td>
</tr>
<tr>
<td>[[Yttrium]]</td>
<td>[[1794]]</td>
<td> [[Johan Gadolin]]</td>
</tr>
<tr>
<td>[[Titanium]]</td>
<td>[[1797]]</td>
<td>[[Martin Heinrich Klaproth]]</td>
</tr>
<tr>
<td>[[Chromium]]</td>
<td>[[1797]]</td>
<td>[[Louis Nicolas Vauquelin]]</td>
</tr>
<tr>
<td>[[Beryllium]]</td>
<td>[[1798]]</td>
<td>[[Louis Nicolas Vauquelin]]</td>
</tr>
<tr>
<td>[[Vanadium]]</td>
<td>[[1801]]</td>
<td>[[Andrés Manuel del Río]]</td>
</tr>
<tr>
<td>[[Niobium]]</td>
<td>[[1801]]</td>
<td> [[Charles Hatchett]] discovered as [[Niobium|Columbium]]</td>
</tr>
<tr>
<td>[[Tantalum]]</td>
<td>[[1802]]</td>
<td>[[Anders Gustaf Ekeberg]]</td>
</tr>
</table>
The next element was discovered just after the discovery of a new
class of astronomical objects: the new element was named after the
newly discovered [[asteroid]], [[1 Ceres|Ceres]]. The element was
discovered nearly simultaneously in two laboratories, though it was
later shown that Berzelius and Hisinger's cerium was actually a
mixture of cerium, lanthanum and didymium.
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Cerium]]</td>
<td>[[1803]]</td>
<td>[[Martin Heinrich Klaproth]]; [[Jöns Jakob Berzelius]] and [[Hisinger]]</td>
</tr>
<tr>
<td>[[Rhodium]]</td>
<td>[[1803]]</td>
<td> [[William Hyde Wollaston]]</td>
</tr>
<tr>
<td>[[Palladium]]</td>
<td>[[1803]]</td>
<td>[[William Hyde Wollaston]]</td>
</tr>
<tr>
<td>[[Osmium]]</td>
<td>[[1803]]</td>
<td> [[Smithson Tennant]]</td>
</tr>
<tr>
<td>[[Iridium]]</td>
<td>[[1803]]</td>
<td> [[Smithson Tennant]]</td>
</tr>
</table>
At this point, Sir [[Humphry Davy]] pioneered the use of [[electricity]]
from the [[Voltaic pile]] to decompose the salts of alkali metals,
and so a number of those metals were first prepared as the pure
element: the beginning of the field of [[electrochemistry]].
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Potassium]]</td>
<td>[[1807]]</td>
<td>[[Humphry Davy]]</td>
</tr>
<tr>
<td>[[Sodium]]</td>
<td>[[1807]]</td>
<td>[[Humphry Davy]]</td>
</tr>
<tr>
<td>[[Calcium]]</td>
<td>[[1808]]</td>
<td>[[Humphry Davy]]</td>
</tr>
<tr>
<td>[[Barium]]</td>
<td>[[1808]]</td>
<td>[[Humphry Davy]]</td>
</tr>
<tr>
<td>[[Boron]]</td>
<td>[[1808]]</td>
<td>[[Joseph Louis Gay-Lussac]] & [[Louis-Jacques Thenard]]</td>
</tr>
<tr>
<td>[[Iodine]]</td>
<td>[[1811]]</td>
<td>[[Bernard Courtois]]</td>
</tr>
<tr>
<td>[[Lithium]]</td>
<td>[[1817]]</td>
<td>[[Johan August Arfwedson]]</td>
</tr>
<tr>
<td>[[Cadmium]]</td>
<td>[[1817]]</td>
<td>[[Friedrich Strohmeyer]] Independently discovered by [[Karl Samuel Leberecht Hermann|K.S.L Hermann]]</td>
</tr>
<tr>
<td>[[Selenium]]</td>
<td>[[1817]]</td>
<td>[[Jöns Jakob Berzelius]]</td>
</tr>
<tr>
<td>[[Silicon]]</td>
<td>[[1823]]</td>
<td>[[Jöns Jakob Berzelius]]</td>
</tr>
<tr>
<td>[[Aluminium]]</td>
<td>[[1825]]</td>
<td>[[Hans Christian Ørsted]] (''may'' have been isolated in Roman times, see [[Aluminium#History]])</td>
</tr>
<tr>
<td>[[Bromine]]</td>
<td>[[1826]]</td>
<td>[[Antoine Jérôme Balard]]</td>
</tr>
<tr>
<td>[[Thorium]]</td>
<td>[[1828]]</td>
<td>[[Jöns Jakob Berzelius]]</td>
</tr>
<tr>
<td>[[Beryllium]]</td>
<td>[[1828]]</td>
<td>[[Friedrich Woehler|Friedrich Wöhler]]. Independently discovered by [[A.A.B. Bussy]]</td>
</tr>
</table>
The next element discovered when Mosander showed that the cerium isolated in [[1803]] by Berzelius was actually a mixture of cerium, lanthanum and so-called didymium (which was not actually one element, and was resolved into two in [[1885]]).
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Lanthanum]]</td>
<td>[[1839]]-41</td>
<td>[[Carl Gustaf Mosander]]</td>
</tr>
<tr>
<td>[[Terbium]]</td>
<td>[[1843]]</td>
<td>[[Carl Gustaf Mosander]]</td>
</tr>
<tr>
<td>[[Erbium]]</td>
<td>[[1843]]</td>
<td>[[Carl Gustaf Mosander]]</td>
</tr>
<tr>
<td>[[Ruthenium]]</td>
<td>[[1844]]</td>
<td>[[Karl Klaus]]</td>
</tr>
</table>
==Spectroscopic discoveries==
A number of elements were first identified by their spectroscopic
[[emission line]]s: caesium and rubidium were discovered by [[Robert Bunsen]] and [[Gustav Kirchhoff]] analysing the spectrum of alkali salts. The unknown element with blue emission lines was named caesium; in purifying the salts of this new element, another element was discovered with a red emission line; this was called rubidium. They were shortly afterwards prepared as the pure salts by Bunsen. The bright green line of thallium caused it to be named from the Greek ''thallos'', meaning a green shoot, and the indigo-blue line from certain
specimens of zinc-blende gave the name indium to the new element so discovered:
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Caesium]]</td>
<td>[[1860]]</td>
<td>[[Robert Bunsen]] and [[Gustav Kirchoff]]</td>
</tr>
<tr>
<td>[[Rubidium]]</td>
<td>[[1860]]</td>
<td>[[Robert Bunsen]] and [[Gustav Kirchoff]]</td>
</tr>
<tr>
<td>[[Thallium]]</td>
<td>[[1861]]</td>
<td>[[Sir William Crookes]]</td>
</tr>
<tr>
<td>[[Indium]]</td>
<td>[[1863]]</td>
<td>[[Ferdinand Reich]] and [[Hieronymous Theodor Richter|Theodor Richter]]</td>
</tr>
</table>
Another spectroscopic discovery, helium was found by astronomers as an emission line in the spectrum of the sun, hence its name from the Greek ''helios'' meaning sun. It was at first thought to be an unknown metallic element, and so the name was given the ending -ium to signify a metal. By the time it had been found on Earth and discovered to be the lightest of the noble gases, the name was fixed; by analogy with the other noble gases, the name should have ended in -on.
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Helium]]</td>
<td>[[1868]]</td>
<td>Independently by [[Pierre Jules César Janssen|Pierre Jansen]] and [[Joseph Norman Lockyer|Norman Lockyer]]</td>
</tr>
</table>
==The Periodic table and the prediction of new elements==
In [[1871]], [[Dmitri Ivanovich Mendeleev|Mendeleev]] predicted, from the gaps in his newly-devised [[periodic table]], that there should be three as yet undiscovered elements, which he named eka-boron, eka-aluminium, and eka-silicon. With Mendeleev's prediction of their existence and approximate chemical properties, the missing elements were found by French, Scandinavian, and German chemists, and named for their countries of discovery, as gallium,
scandium, and germanium:
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Gallium]]</td>
<td>[[1875]]</td>
<td>[[Paul Emile Lecoq de Boisbaudran]]</td>
</tr>
<tr>
<td>[[Ytterbium]]</td>
<td>[[1878]]</td>
<td>[[Jean Charles Galissard de Marignac]]</td>
</tr>
<tr>
<td>[[Thulium]]</td>
<td>[[1879]]</td>
<td>[[Per Teodor Cleve]]</td>
</tr>
<tr>
<td>[[Scandium]]</td>
<td>[[1879]]</td>
<td>[[Lars Fredrik Nilson]]</td>
</tr>
<tr>
<td>[[Holmium]]</td>
<td>[[1879]]</td>
<td>[[Marc Delafontaine]], [[Jacques-Louis Soret]] and [[Per Teodor Cleve]]</td>
</tr>
<tr>
<td>[[Samarium]]</td>
<td>[[1879]]</td>
<td>[[Paul Emile Lecoq de Boisbaudran]]</td>
</tr>
<tr>
<td>[[Gadolinium]]</td>
<td>[[1880]]</td>
<td>[[Jean Charles Galissard de Marignac]]</td>
</tr>
</table>
The 'didymium' isolated by Mosander in [[1839]] was shown to
actually be two separate elements, praseodymium and neodymium:
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Praseodymium]]</td>
<td>[[1885]]</td>
<td>[[Carl Auer von Welsbach]]</td>
</tr>
<tr>
<td>[[Neodymium]]</td>
<td>[[1885]]</td>
<td>[[Carl Auer von Welsbach]]</td>
</tr>
<tr>
<td>[[Dysprosium]]</td>
<td>[[1886]]</td>
<td>[[Paul Emile Lecoq de Boisbaudran]]</td>
</tr>
<tr>
<td>[[Germanium]]</td>
<td>[[1886]]</td>
<td>[[Clemens Winkler]]</td>
</tr>
<tr>
<td>[[Fluorine]]</td>
<td>[[1886]]</td>
<td> [[Joseph Henri Moissan]]</td>
</tr>
</table>
[[Refrigeration]] technology advanced considerably during the [[19th century]], to the point where it was possible to liquefy atmospheric
gases. A curious observation was made: Nitrogen prepared by
chemical means from its compounds had a slightly lower molecular
weight than nitrogen prepared by liquefaction from air. This was
attributed as being due to the presence of a previously unsuspected
gas, christened argon. This gas was the first representative found
of a previously unsuspected new group in the periodic table, first
known as the inert gases, now more commonly known as the [[noble gas|noble gases]].
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Argon]]</td>
<td>[[1894]]</td>
<td>[[John William Strutt, 3rd Baron Rayleigh|Lord Rayleigh]] & [[Sir William Ramsay]]</td>
</tr>
</table>
Once liquid argon could be prepared in quantity from air, small
amounts of a further three noble gases could be separated from it
by differences in boiling point. These new elements were named from
the Greek words for, respectively, 'new', 'hidden', and 'foreign'.
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Neon]]</td>
<td>[[1898]]</td>
<td>Sir [[William Ramsay]]</td>
</tr>
<tr>
<td>[[Krypton]]</td>
<td>[[1898]]</td>
<td>Sir [[William Ramsay]]</td>
</tr>
<tr>
<td>[[Xenon]]</td>
<td>[[1898]]</td>
<td>Sir [[William Ramsay]]</td>
</tr>
</table>
With the discovery of [[radioactivity]], we have the classic work
by the Curies that isolated a number of previously unknown
elements:
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Radium]]</td>
<td>[[1898]]</td>
<td>[[Pierre Curie]] and [[Maria Sklodowska-Curie]]</td>
</tr>
<tr>
<td>[[Polonium]]</td>
<td>[[1898]]</td>
<td>[[Pierre Curie]] and [[Maria Sklodowska-Curie]]</td>
</tr>
</table>
Another of the noble gases, radon had avoided discovery because its
short radioactive half-life had meant it was present in air in
vanishingly tiny quantities. Once radium was available in
macroscopic quantities, the production of this radioactive noble
gas was readily detected as a product of radium's radioactive
decay.
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Radon]]</td>
<td>[[1898]]</td>
<td>[[Friedrich Ernst Dorn]] who called it nitron</td>
</tr>
<tr>
<td>[[Actinium]]</td>
<td>[[1899]]</td>
<td>[[André-Louis Debierne]]</td>
</tr>
<tr>
<td>[[Europium]]</td>
<td>[[1901]]</td>
<td>[[Eugene Demarcay]]</td>
</tr>
<tr>
<td>[[Lutetium]]</td>
<td>[[1907]]</td>
<td>[[Georges Urbain]]</td>
</tr>
<tr>
<td>[[Protactinium]]</td>
<td>[[1917]]</td>
<td>[[Kasimir Fajans]], [[O. Göhring]], [[Fredrich Soddy]], [[John Cranston]], [[Lise Meitner]] and [[Otto Hahn]]</td>
</tr>
<tr>
<td>[[Hafnium]]</td>
<td>[[1923]]</td>
<td>[[Dirk Coster]]</td>
</tr>
<tr>
<td>[[Rhenium]]</td>
<td>[[1925]]</td>
<td>[[Walter Noddack]] and [[Ida Tacke]]</td>
</tr>
</table>
At this point, all the [[stable element]]s existing on earth had been discovered, and most of the periodic table had been filled. A few gaps remained amongst the higher mass elements, but there remained a troublesome gap at element number 43, just below manganese in the table. The gaps were filled by the synthetic elements. Walter Noddack and Ida Tacke (later Ida Noddack) also believed to have found Technetium, which they called Masurium (after Masurien, an area in Germany). They were later proved wrong.
===The [[synthetic element]]s===
The so-called "synthetic" elements are unstable, with [[half-life|half-lives]] so "short" relative to the age of the earth that any atoms of that element that may have been present when the earth formed have long since completely decayed away. Hence they are only known on earth as the product of [[nuclear reactor]]s, [[particle accelerator]]s, or in the byproducts from [[nuclear explosion]]s. The discovery of technetium finally filled in a puzzling gap in the [[periodic table]], and the discovery that there were no stable isotopes of technetium
explained its absence on earth: its [[1e14 s|4.2 million years]] half-life meant that none remained from the time of formation of the earth.
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Technetium]]</td>
<td>[[1937]]</td>
<td>[[Carlo Perrier]]</td>
</tr>
<tr>
<td>[[Francium]] (natural)</td>
<td>[[1939]]</td>
<td>[[Marguerite Derey]]</td>
</tr>
</table>
All elements after this are synthetic:
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Astatine]]</td>
<td>[[1940]]</td>
<td>[[Dale R. Corson]], [[K.R.Mackenzie]], [[Emilio Segrè]]</td>
</tr>
</table>
The next two elements were the first of the [[transuranium element|transuranic (beyond uranium) elements]] and were named after the planets beyond [[Uranus (planet)|Uranus]], [[Neptune (planet)|Neptune]] and [[Pluto (planet)|Pluto]]:
<table border="1" cellspacing="0" cellpadding="2" width="75%">
<tr>
<th width="15%">Name</th>
<th width="10%">Date</th>
<th width="70%">Discoverer</th>
</tr>
<tr>
<td>[[Neptunium]]</td>
<td>[[1940]]</td>
<td>[[Edwin McMillan|E.M. McMillan]] & [[Philip H. Abelson]],
[[University of California, Berkeley]]</td>
</tr>
<tr>
<td>[[Plutonium]]</td>
<td>[[1941]]</td>
<td>[[Glenn T. Seaborg]], [[Arthur C. Wahl]], [[Joseph W. Kennedy]], [[Emilio Segrè]]</td>
</tr>
<tr>
<td>[[Curium]]</td>
<td>[[1944]]</td>
<td>[[Glenn T. Seaborg]]</td>
</tr>
<tr>
<td>[[Americium]]</td>
<td>[[1945]]</td>
<td>[[Glenn T. Seaborg]]</td>
</tr>
<tr>
<td>[[Promethium]]</td>
<td>[[1945]]</td>
<td>[[J.A. Marinsky]]</td>
</tr>
<tr>
<td>[[Berkelium]]</td>
<td>[[1949]]</td>
<td>[[Albert Ghiorso]], [[Glenn T. Seaborg]], [[Stanley G. Thompson]], [[Kenneth Street Jr.]]</td>
</tr>
<tr>
<td>[[Californium]]</td>
<td>[[1950]]</td>
<td>[[Albert Ghiorso]], [[Glenn T. Seaborg]], [[Stanley G. Thompson]], [[Kenneth Street Jr.]]</td>
</tr>
<tr>
<td>[[Einsteinium]]</td>
<td>[[1952]]</td>
<td>[[Argonne Laboratory]], [[Los Alamos Laboratory]], and [[University of California]]</td>
</tr>
<tr>
<td>[[Fermium]]</td>
<td>[[1953]]</td>
<td>[[Argonne Laboratory]], [[Los Alamos Laboratory]], and [[University of California]]</td>
</tr>
<tr>
<td>[[Mendelevium]]</td>
<td>[[1955]]</td>
<td>[[Glenn T. Seaborg]], [[Evans G. Valens]]</td>
</tr>
<tr>
<td>[[Nobelium]]</td>
<td>[[1958]]</td>
<td>[[Albert Ghiorso]], [[Glenn T. Seaborg]], [[John R. Walton]] and [[Torbørn Sikkeland]]</td>
</tr>
<tr>
<td>[[Lawrencium]]</td>
<td>[[1961]]</td>
<td> [[Albert Ghiorso]], [[Torbjørn Sikkeland]], [[Almon Larsh]] and [[Robert M. Latimer]]</td>
</tr>
<tr>
<td>[[Rutherfordium]]</td>
<td>[[1964]]</td>
<td>[[Joint Institute for Nuclear Research]] at Dubna, U.S.S.R.</td>
</tr>
<tr>
<td>[[Dubnium]]</td>
<td>[[1970]]</td>
<td>[[Albert Ghiorso]]</td>
</tr>
<tr>
<td>[[Seaborgium]]</td>
<td>[[1974]]</td>
<td> [[Joint Institute for Nuclear Research]] and [[University of California, Berkeley]]</td>
</tr>
<tr>
<td>[[Bohrium]]</td>
<td>[[1976]]</td>
<td>[[Y. Oganessian]] et al, [[Dubna]] and confirmed at [[Gesellschaft für Schwerionenforschung|GSI]] (1982)</td>
</tr>
<tr>
<td>[[Meitnerium]]</td>
<td>[[1982]]</td>
<td>[[Peter Armbruster]] and [[Gottfried Münzenberg]], [[Gesellschaft für Schwerionenforschung|GSI]]</td>
</tr>
<tr>
<td>[[Hassium]]</td>
<td>[[1984]]</td>
<td> [[Peter Armbruster]] and [[Gottfried Münzenberg]]</td>
</tr>
<tr>
<td>[[Darmstadtium]]</td>
<td>[[1994]]</td>
<td>[[S. Hofmann]], [[V. Ninov]] et al, [[Gesellschaft für Schwerionenforschung|GSI]]</td>
</tr>
<tr>
<td>[[Roentgenium]]</td>
<td>[[1994]]</td>
<td>[[S. Hofmann]], [[V. Ninov]] et al, [[Gesellschaft für Schwerionenforschung|GSI]]</td>
</tr>
<tr>
<td>[[Ununbium]]</td>
<td>[[1996]]</td>
<td>[[S. Hofmann]], [[V. Ninov]] et al, [[Gesellschaft für Schwerionenforschung|GSI]]</td>
</tr>
<tr>
<td>[[Ununquadium]]</td>
<td>[[1999]]</td>
<td>[[Joint Institute for Nuclear Research]] at Dubna</td>
</tr>
<tr>
<td>[[Ununhexium]]</td>
<td>[[2001]]</td>
<td>[[Joint Institute for Nuclear Research]] at Dubna</td>
</tr>
<tr>
<td>[[Ununtrium]]</td>
<td>[[2004]]</td>
<td> [[Joint Institute for Nuclear Research]] at Dubna and [[Lawrence Livermore National Laboratory]]</td>
</tr>
<tr>
<td>[[Ununpentium]]</td>
<td>[[2004]]</td>
<td> [[Joint Institute for Nuclear Research]] at Dubna and [[Lawrence Livermore National Laboratory]]</td>
</tr>
</table>
== See also ==
* [[Periodic table]]
* [[Elements song]]
* [[Timeline of chemical element discovery]]
[[Category:History of chemistry]]
[[Category:History of physics]]
[[Category:Chemical elements|*]]
[[Category:Discoverer of a chemical element|*]]
[[pt:Descoberta dos elementos químicos]]
[[it:Scoperta degli elementi chimici]]
| 