Timeline of chemical element discoveries

The discovery of the 118 chemical elements known to exist as of 2023 is presented here in chronological order. The elements are listed generally in the order in which each was first defined as the pure element, as the exact date of discovery of most elements cannot be accurately determined. There are plans to synthesize more elements, and it is not known how many elements are possible.

Each element's name, atomic number, year of first report, name of the discoverer, and notes related to the discovery are listed.

Periodic table of elements

Periodic table by era of discovery
	1	2		3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
Group →
↓ Period
1	1 H																		2 He
2	3 Li	4 Be												5 B	6 C	7 N	8 O	9 F	10 Ne
3	11 Na	12 Mg												13 Al	14 Si	15 P	16 S	17 Cl	18 Ar
4	19 K	20 Ca		21 Sc	22 Ti	23 V	24 Cr	25 Mn	26 Fe	27 Co	28 Ni	29 Cu	30 Zn	31 Ga	32 Ge	33 As	34 Se	35 Br	36 Kr
5	37 Rb	38 Sr		39 Y	40 Zr	41 Nb	42 Mo	43 Tc	44 Ru	45 Rh	46 Pd	47 Ag	48 Cd	49 In	50 Sn	51 Sb	52 Te	53 I	54 Xe
6	55 Cs	56 Ba		71 Lu	72 Hf	73 Ta	74 W	75 Re	76 Os	77 Ir	78 Pt	79 Au	80 Hg	81 Tl	82 Pb	83 Bi	84 Po	85 At	86 Rn
7	87 Fr	88 Ra		103 Lr	104 Rf	105 Db	106 Sg	107 Bh	108 Hs	109 Mt	110 Ds	111 Rg	112 Cn	113 Nh	114 Fl	115 Mc	116 Lv	117 Ts	118 Og
				57 La	58 Ce	59 Pr	60 Nd	61 Pm	62 Sm	63 Eu	64 Gd	65 Tb	66 Dy	67 Ho	68 Er	69 Tm	70 Yb
				89 Ac	90 Th	91 Pa	92 U	93 Np	94 Pu	95 Am	96 Cm	97 Bk	98 Cf	99 Es	100 Fm	101 Md	102 No
Background color shows age of discovery: Antiquity to 1600 1600–​1799 1800–​1849 1850–​1899 1900–​1949 1950–​1999 Since 2000 (14 elements) Antiquity to 1600: ancient to early modern discoveries (27 elements) Discoveries during the Scientific Revolution and the age of enlightenment, part of the gradual rejection of the Aristotelian theory of matter, and Lavoisier's definition of a chemical element (19 elements) The chemical and industrial revolutions lead to the standardization of chemical techniques and the development of atomic theory for chemistry (23 elements) The age of classifying elements and Mendeleev's periodic table; application of spectrum analysis techniques: Boisbaudran, Bunsen, Crookes, Kirchhoff, and others "hunting emission line signatures" (14 elements) Developments in X-ray spectroscopy and radiochemistry allows for many radioactive elements and the final stable elements to be discovered; recognition of the atomic number as defining an element (16 elements) Post Manhattan project; synthesis of atomic numbers 98 and above (colliders, bombardment techniques, nuclear reactors) (5 elements) Recent synthesis Primordial  From decay  Synthetic Border shows natural occurrence of the element

Pre-modern and early modern discoveries

Z	Element	Earliest use	Oldest existing sample	Discoverer(s)	Place of oldest sample	Notes
29	Copper	9000 BC	6000 BC	Middle East	Anatolia	Copper was probably the first metal mined and crafted by humans. It was originally obtained as a native metal and later from the smelting of ores. Earliest estimates of the discovery of copper suggest around 9000 BC in the Middle East. It was one of the most important materials to humans throughout the Chalcolithic and Bronze Ages. Copper beads dating from 6000 BC have been found in Çatalhöyük, Anatolia and the archaeological site of Belovode on the Rudnik mountain in Serbia contains the world's oldest securely dated evidence of copper smelting from 5000 BC. Recognised as an element by Louis Guyton de Morveau, Antoine Lavoisier, Claude Berthollet, and Antoine-François de Fourcroy in 1787.
82	Lead	7000 BC	3800 BC	Asia Minor	Abydos, Egypt	It is believed that lead smelting began at least 9,000 years ago, and the oldest known artifact of lead is a statuette found at the temple of Osiris on the site of Abydos dated around 3800 BC. Recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy in 1787.
79	Gold	Before 6000 BC	Before 4000 BC	Levant	Wadi Qana	The earliest gold artifacts were discovered at the site of Wadi Qana in the Levant. Recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy in 1787.
47	Silver	Before 5000 BC	ca. 4000 BC	Asia Minor	Asia Minor	Estimated to have been discovered in Asia Minor shortly after copper and gold. Recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy in 1787.
26	Iron	Before 5000 BC	4000 BC	Middle East	Egypt	There is evidence that iron was known from before 5000 BC. The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in about 4000 BC. The discovery of smelting around 3000 BC led to the start of the Iron Age around 1200 BC and the prominent use of iron for tools and weapons. Recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy in 1787.
6	Carbon	3750 BC	2500 BC	Egyptians and Sumerians	Middle East	Charcoal and soot were known to the earliest humans. The earliest known use of charcoal was for the reduction of copper, zinc, and tin ores in the manufacture of bronze, by the Egyptians and Sumerians. Diamonds were probably known as early as 2500 BC. True chemical analyses were made in the 18th century, and in 1772 Antoine Lavoisier demonstrated that diamond, graphite, and charcoal are all composed of the same substance. In 1787, de Morveau, Fourcroy, and Lavoisier listed carbon (in French, carbone) as an element, distinguishing it from coal (in French, charbon).
50	Tin	3500 BC	2000 BC	Asia Minor	Kestel	First smelted in combination with copper around 3500 BC to produce bronze (and thus giving place to the Bronze Age in those places where Iron Age did not intrude directly on Neolithic of the Stone Age). Kestel, in southern Turkey, is the site of an ancient Cassiterite mine that was used from 3250 to 1800 BC. The oldest artifacts date from around 2000 BC. Recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy in 1787.
16	Sulfur	Before 2000 BC		Middle East	Middle East	First used at least 4,000 years ago. According to the Ebers Papyrus, a sulfur ointment was used in ancient Egypt to treat granular eyelids. Designated as one of the two elements of which all metals are composed in the sulfur-mercury theory of metals, first described in pseudo-Apollonius of Tyana's Sirr al-khaliqa ('Secret of Creation') and in the works attributed to Jabir ibn Hayyan (both 8th or 9th century). Designated as a universal element (one of the tria prima) by Paracelsus in the early 16th century. Recognized as an element by Lavoisier in 1777, which was supported by John Dalton in 1808 and confirmed by Joseph Gay-Lussac and Louis Jacques Thénard in 1810.
80	Mercury	1500 BC	1500 BC	Egyptians	Egypt	Found in Egyptian tombs dating from 1500 BC. Recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy in 1787.
30	Zinc	Before 1000 BC	1000 BC	Indian metallurgists	Indian subcontinent	Used as a component of brass since antiquity (before 1000 BC) by Indian metallurgists, but its true nature was not understood in ancient times. Zinc smelting was done in China and India around 1300. Identified as a distinct metal in the Rasaratna Samuccaya around the 14th century of the Christian era and by the alchemist Paracelsus in 1526, who gave it its present name and described it as a new metal. P. M. de Respour isolated it from zinc oxide in 1668; the first detailed documentation of zinc isolation was given by Andreas Sigismund Marggraf in 1746.
78	Platinum	c. 600 BC – AD 200	c. 600 BC – AD 200	Pre-Columbian South Americans	South America	Used by pre-Columbian Americans near modern-day Esmeraldas, Ecuador to produce artifacts of a white gold-platinum alloy, although precise dating is difficult. First European description of a metal found in South American gold was in 1557 by Julius Caesar Scaliger. Antonio de Ulloa was on an expedition to Peru in 1735, where he observed the metal; he published his findings in 1748. Sir Charles Wood also investigated the metal in 1741. First reference to it as a new metal was made by William Brownrigg in 1750.
33	Arsenic	c. 850–950	c. 850–950	Jabir ibn Hayyan	Middle East	The use of metallic arsenic was described by the Egyptian alchemist Zosimos. The purification of arsenic was later described in the works attributed to the Muslim alchemist Jabir ibn Hayyan (c. 850–950). Albertus Magnus (c. 1200–1280) is typically credited with the description of the metal in the West, though some question his work and instead credit Vannoccio Biringuccio, whose De la pirotechnia (1540) distinguishes orpiment from crystalline arsenic. The first to unquestionably have prepared metallic arsenic was Johann Schröder in 1641. Recognised as an element after Lavoisier's definition in 1787.
51	Antimony	c. 850–950	c. 850–950	Jabir ibn Hayyan	Middle East	Dioscorides and Pliny both describe the accidental production of metallic antimony from stibnite, but only seem to recognize the metal as lead. The intentional isolation of antimony is described in the works attributed to the Muslim alchemist Jabir ibn Hayyan (c. 850–950). In Europe, the metal was being produced and used by 1540, when it was described by Vannoccio Biringuccio. Described again by Georgius Agricola De re metallica in 1556. Probably first recognised as an element by Lavoisier in 1787.
83	Bismuth	c. 1500	c. 1500	European alchemists and Inca civilisation	Europe and South America	Bismuth was known since ancient times, but often confused with tin and lead, which are chemically similar. The Incas used bismuth (along with the usual copper and tin) in a special bronze alloy for knives. Agricola (1530 and 1546) states that bismuth is a distinct metal in a family of metals including tin and lead. This was based on observation of the metals and their physical properties. Miners in the age of alchemy also gave bismuth the name tectum argenti, or "silver being made" in the sense of silver still in the process of being formed within the Earth. Beginning with Johann Heinrich Pott in 1738, Carl Wilhelm Scheele, and Torbern Olof Bergman, the distinctness of lead and bismuth became clear, and Claude François Geoffroy demonstrated in 1753 that this metal is distinct from lead and tin.

Modern discoveries

For 18th-century discoveries, around the time that Antoine Lavoisier first questioned the phlogiston theory, the recognition of a new "earth" has been regarded as being equivalent to the discovery of a new element (as was the general practice then). For some of the most common elements, this presents further difficulties as their compounds were widely known since medieval or even ancient times, and their true nature was only gradually discovered, so it is very difficult to name one specific discoverer. In such cases the first publication on their chemistry is noted, and a longer explanation given in the notes.

Z	Element	Observed or predicted		Isolated (widely known)		Notes
			By		By
15	Phosphorus	1669	H. Brand	1669	H. Brand	Prepared and isolated from urine, it was the first element whose discovery date and discoverer is recorded. Its name first appears in print in the work of Georg Kaspar Kirchmayer in 1676. Recognised as an element by Lavoisier.
11	Sodium	1702	G. E. Stahl	1807	H. Davy	Georg Ernst Stahl obtained experimental evidence that led him to suggest the fundamental difference of sodium and potassium salts in 1702, and Henri Louis Duhamel du Monceau was able to prove this difference in 1736. Andreas Sigismund Marggraf again recognised the difference between soda ash and potash in 1758, but not all chemists accepted his conclusion. In 1797, Martin Heinrich Klaproth suggested the names natron and kali for the two alkalis (whence the symbols). Davy isolated sodium metal a few days after potassium, by using electrolysis on sodium hydroxide.
19	Potassium	1702	G. E. Stahl	1807	H. Davy	Georg Ernst Stahl obtained experimental evidence that led him to suggest the fundamental difference of sodium and potassium salts in 1702, and Henri Louis Duhamel du Monceau was able to prove this difference in 1736. Andreas Sigismund Marggraf again recognised the difference between soda ash and potash in 1758, but not all chemists accepted his conclusion. In 1797, Martin Heinrich Klaproth suggested the names natron and kali for the two alkalis (whence the symbols). Davy isolated potassium metal by using electrolysis on potash.
27	Cobalt	1735	G. Brandt	1735	G. Brandt	Proved that the blue color of glass is due to a new kind of metal and not bismuth as thought previously.
20	Calcium	1739	J. H. Pott	1808	H. Davy	Lime was known as a substance for centuries, but only in the 18th century was its chemical nature recognised. Pott recognised terra calcarea (calcareous earth) as an individual "earth" in his treatise of 1739. Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy suggested in 1787 that it was the oxide of an element. Davy isolated the metal electrochemically from quicklime.
14	Silicon	1739	J. H. Pott	1823	J. Berzelius	Silicon compounds (rock crystals and glass) were known to the ancients, but its chemical investigation dates only to the 17th century. Johann Joachim Becher (of the phlogiston theory) identified silica as the terra vitrescibilis, and Johann Heinrich Pott recognised it as an individual "earth" in his treatise of 1739. Silica appears as a "simple earth" in the Méthode de nomenclature chimique, and in 1789 Lavoisier concluded that the element must exist. Davy thought in 1800 that silica was a compound, not an element, and in 1808 he proved this although he could not isolate the element, and suggested the name silicium. In 1811 Louis-Joseph Gay-Lussac and Louis-Jacques Thénard probably prepared impure silicon, and Berzelius obtained the pure element in 1823. The name was proposed to be changed to silicon by Thomas Thomson in 1817, and this was eventually accepted because of its analogies to boron and carbon.
13	Aluminium	1746	J. H. Pott	1824	H.C.Ørsted	Paracelsus recognised aluminis as separate from vitriol in 1570, and Andreas Libavius proposed in his 1597 treatise to name the unknown earth of alum alumina. In 1746, Johann Heinrich Pott published a treatise distinguishing alum from lime and chalk, and Marggraf precipitated the new earth in 1756. Antoine Lavoisier predicted in 1787 that alumina is the oxide of an undiscovered element, and in 1808 Davy tried to decompose it. Although he failed, he proved Lavoisier correct and suggested the present name. Hans Christian Ørsted was the first to isolate metallic aluminium in 1824.
28	Nickel	1751	F. Cronstedt	1751	F. Cronstedt	Found by attempting to extract copper from the mineral known as fake copper (now known as niccolite).
12	Magnesium	1755	J. Black	1808	H. Davy	Joseph Black observed that magnesia alba (MgO) was not quicklime (CaO) in 1755; until then both substances were confused. Davy isolated the metal electrochemically from magnesia.
1	Hydrogen	1766	H. Cavendish	1766	H. Cavendish	Cavendish was the first to distinguish H 2 from other gases, although Paracelsus around 1500, Robert Boyle, and Joseph Priestley had observed its production by reacting strong acids with metals. Lavoisier named it in 1783. It was the first elemental gas known.
9	Fluorine	1771	W. Scheele	1886	H. Moissan	Scheele studied fluorspar and correctly concluded it to be the lime (calcium) salt of an acid. Radical fluorique appears on the list of elements in Lavoisier's Traité Élémentaire de Chimie from 1789, but radical muriatique also appears instead of chlorine. André-Marie Ampère again predicted in 1810 that hydrofluoric acid contained an element analogous to chlorine, and between 1812 and 1886 many researchers tried to obtain it. It was eventually isolated by Moissan.
8	Oxygen	1771	W. Scheele	1771	W. Scheele	Scheele obtained it by heating mercuric oxide and nitrates in 1771, but did not publish his findings until 1777. Joseph Priestley also prepared this new air by 1774, but only Lavoisier recognized it as a true element; he named it in 1777. Before him, Sendivogius had produced oxygen by heating saltpetre, correctly identifying it as the "food of life".
7	Nitrogen	1772	D. Rutherford	1772	D. Rutherford	Rutherford discovered nitrogen while studying at the University of Edinburgh. He showed that the air in which animals had breathed, even after removal of the exhaled carbon dioxide, was no longer able to burn a candle. Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley also studied the element at about the same time, and Lavoisier named it in 1775–6.
56	Barium	1772	W. Scheele	1808	H. Davy	Scheele distinguished a new earth (BaO) in pyrolusite in 1772. He did not name his discovery; Guyton de Morveau suggested barote in 1782. It was changed to baryte in the Méthode de nomenclature chimique of Louis-Bernard Guyton de Morveau, Antoine Lavoisier, Claude Louis Berthollet, and Antoine François, comte de Fourcroy (1787). Davy isolated the metal by electrolysis.
25	Manganese	1774	W. Scheele	1774	J. G. Gahn	Distinguished pyrolusite as the calx of a new metal. Ignatius Gottfred Kaim might have isolated it in 1770, but there is uncertainty on that. It was isolated by reduction of manganese dioxide with carbon. Given its present name in 1779 by Guyton de Morveau; prior to that it was called magnesia.
17	Chlorine	1774	W. Scheele	1774	W. Scheele	Obtained it from hydrochloric acid, but thought it was an oxide. Only in 1808 did Humphry Davy recognize it as an element.
42	Molybdenum	1778	W. Scheele	1788	J. Hjelm	Scheele recognised the metal as a constituent of molybdena. Before that, Axel Cronstedt had assumed that molybdena contained a new earth in 1758.
74	Tungsten	1781	W. Scheele	1783	J. and F. Elhuyar	Scheele showed that scheelite (then called tungsten) was a salt of calcium with a new acid, which he called tungstic acid. The Elhuyars obtained tungstic acid from wolframite and reduced it with charcoal, naming the element "volfram". Since that time both names, tungsten and wolfram, have been used depending on language. In 1949 IUPAC made wolfram the scientific name, but this was repealed after protest in 1951 in favour of recognising both names pending a further review (which never materialised). Currently only tungsten is recognised for use in English.
52	Tellurium	1782	F.-J.M. von Reichenstein	1798	H. Klaproth	Muller observed it as an impurity in gold ores from Transylvania. Klaproth isolated it in 1798.
38	Strontium	1787	W. Cruikshank	1808	H. Davy	W. Cruikshank in 1787 and Adair Crawford in 1790 concluded that strontianite contained a new earth. It was eventually isolated electrochemically in 1808 by Davy.
5	Boron	1787	L. Guyton de Morveau, A. Lavoisier, C. L. Berthollet, and A. de Fourcroy	1809	H. Davy	Borax was known from ancient times. In 1787, radical boracique appeared in the Méthode de nomenclature chimique of Louis-Bernard Guyton de Morveau, Antoine Lavoisier, Claude Louis Berthollet, and Antoine François, comte de Fourcroy. It also appears in Lavoisier's Traité Élémentaire de Chimie from 1789. In 1808, Lussac and Thénard announced a new element in sedative salt and named it bore. Davy announced the isolation of a new substance from boracic acid in 1809, naming it boracium. As the element turned out not to be a metal, he revised his proposal to boron in 1812.
		1789	A. Lavoisier			Lavoisier writes the first modern list of chemical elements – containing 33 elements including light and heat but omitting Na, K (he was unsure of whether soda and potash without carbonic acid, i.e. Na2O and K2O, are simple substances or compounds like NH3), Sr, Te; some elements were listed in the table as unextracted "radicals" (Cl, F, B) or as oxides (Ca, Mg, Ba, Al, Si). He also redefines the term "element". Until then, no metals except mercury were considered elements.
40	Zirconium	1789	H. Klaproth	1824	J. Berzelius	Martin Heinrich Klaproth identified a new oxide in zircon in 1789, and in 1808 Davy showed that this oxide has a metallic base although he could not isolate it.
92	Uranium	1789	H. Klaproth	1841	E.-M. Péligot	Klaproth mistakenly identified a uranium oxide obtained from pitchblende as the element itself and named it after the recently discovered planet Uranus.
22	Titanium	1791	W. Gregor	1825	J. Berzelius	Gregor found an oxide of a new metal in ilmenite; Klaproth independently discovered the element in rutile in 1795 and named it. The pure metallic form was only obtained in 1910 by Matthew A. Hunter.
39	Yttrium	1794	J. Gadolin	1843	H. Rose	Johan Gadolin discovered the earth in gadolinite in 1794. He did not name his discovery, but Andreas Ekeberg did so when he confirmed it in 1797. Mosander showed later that its ore, yttria, contained more elements. In 1808, Davy showed that yttria is a metallic oxide, although he could not isolate the metal. Wöhler mistakenly thought he had isolated the metal in 1828 from a volatile chloride he supposed to be yttrium chloride, but Rose proved otherwise in 1843 and correctly isolated the element himself that year.
24	Chromium	1797	N. Vauquelin	1798	N. Vauquelin	Vauquelin analysed the composition of crocoite ore in 1797, and later isolated the metal by heating the oxide in a charcoal oven.
4	Beryllium	1798	N. Vauquelin	1828	F. Wöhler and A. Bussy	Vauquelin discovered the oxide in beryl and emerald in 1798, and in 1808 Davy showed that this oxide has a metallic base although he could not isolate it. Vauquelin was uncertain about the name to give to the oxide: in 1798 he called it la terre du beril, but the journal editors named it glucine after the sweet taste of beryllium compounds (which are highly toxic). Johann Heinrich Friedrich Link proposed in 1799 to change the name from Glucine to Beryllerde or Berylline (because glucine resembled glycine), a suggestion taken up by Klaproth in 1800 in the form beryllina. Klaproth had independently worked on beryl and emerald and likewise concluded that a new element was present. The name beryllium for the element was first used by Wöhler upon its isolation (Davy used the name glucium). Both names beryllium and glucinium were used (the latter mostly in France) until IUPAC decided on the name beryllium in 1949.
23	Vanadium	1801	A. M. del Río	1867	H.E.Roscoe	Andrés Manuel del Río found the metal (calling it erythronium) in vanadinite in 1801, but the claim was rejected after Hippolyte Victor Collet-Descotils dismissed it as chromium based on erroneous and superficial testing. Nils Gabriel Sefström rediscovered the element in 1830 and named it vanadium. Friedrich Wöhler then showed that vanadium was identical to erythronium and thus that del Río had been right in the first place. Del Río then argued passionately that his old claim be recognised, but the element kept the name vanadium.
41	Niobium	1801	C. Hatchett	1864	W. Blomstrand	Hatchett found the element in columbite ore and named it columbium. In 1809, W. H. Wollaston claimed that columbium and tantalum are identical, which proved to be false. Heinrich Rose proved in 1844 that the element is distinct from tantalum, and renamed it niobium. American scientists generally used the name columbium, while European ones used niobium. Niobium was officially accepted by IUPAC in 1949.
73	Tantalum	1802	G. Ekeberg			Ekeberg found another element in minerals similar to columbite, and named it after Tantalus from Greek mythology because of its inability to be dissolved by acids (just as Tantalus was tantalised by water that receded when he tried to drink it). In 1809, W. H. Wollaston claimed that columbium and tantalum are identical, which proved to be false. In 1844, Heinrich Rose proved that the elements were distinct and renamed columbium to niobium (Niobe is the daughter of Tantalus).
46	Palladium	1802	W. H. Wollaston	1802	W. H. Wollaston	Wollaston discovered it in samples of platinum from South America, but did not publish his results immediately. He had intended to name it after the newly discovered asteroid, Ceres, but by the time he published his results in 1804, cerium had taken that name. Wollaston named it after the more recently discovered asteroid Pallas.
58	Cerium	1803	H. Klaproth, J. Berzelius, and W. Hisinger	1826	G. Mosander	Berzelius and Hisinger discovered the element in ceria and named it after the newly discovered asteroid (then considered a planet), Ceres. Klaproth discovered it simultaneously and independently in some tantalum samples. Mosander proved later that the samples of all three researchers had at least another element in them, lanthanum.
76	Osmium	1803	S. Tennant	1803	S. Tennant	Tennant had been working on samples of South American platinum in parallel with Wollaston and discovered two new elements, which he named osmium and iridium.
77	Iridium	1803	S. Tennant and H.-V. Collet-Descotils	1803	S. Tennant	Tennant had been working on samples of South American platinum in parallel with Wollaston and discovered two new elements, which he named osmium and iridium, and published the iridium results in 1804. Collet-Descotils also found iridium the same year, but not osmium.
45	Rhodium	1804	H. Wollaston	1804	H. Wollaston	Wollaston discovered and isolated it from crude platinum samples from South America.
53	Iodine	1811	B. Courtois	1811	B. Courtois	Courtois discovered it in the ashes of seaweed. The name iode was given in French by Gay-Lussac and published in 1813. Davy gave it the English name iodine in 1814.
3	Lithium	1817	A. Arfwedson	1821	W. T. Brande	Arfwedson, a student of Berzelius, discovered the alkali in petalite. Brande isolated it electrolytically from lithium oxide.
48	Cadmium	1817	S. L Hermann, F. Stromeyer, and J.C.H. Roloff	1817	S. L Hermann, F. Stromeyer, and J.C.H. Roloff	All three found an unknown metal in a sample of zinc oxide from Silesia, but the name that Stromeyer gave became the accepted one.
34	Selenium	1817	J. Berzelius and G. Gahn	1817	J. Berzelius and G. Gahn	While working with lead they discovered a substance that they thought was tellurium, but realized after more investigation that it was different.
35	Bromine	1825	J. Balard and C. Löwig	1825	J. Balard and C. Löwig	They both discovered the element in the autumn of 1825. Balard published his results the next year, but Löwig did not publish until 1827.
90	Thorium	1829	J. Berzelius	1914	D. Lely, Jr. and L. Hamburger	Berzelius obtained the oxide of a new earth in thorite.
57	Lanthanum	1838	G. Mosander	1841	G. Mosander	Mosander found a new element in samples of ceria and published his results in 1842, but later he showed that this lanthana contained four more elements.
60	Neodymium	1841	G. Mosander	1885	C. A. von Welsbach	Discovered by Mosander and called didymium. Carl Auer von Welsbach later split it into two elements, praseodymium and neodymium. Neodymium had formed the greater part of the old didymium and received the prefix "neo-".
68	Erbium	1843	G. Mosander	1879	T. Cleve	Mosander managed to split the old yttria into yttria proper and erbia, and later terbia too. The names underwent some confusion: Mosander's erbia was yellow and his terbia was red. But in 1860, Nils Johan Berlin could only find the rose-coloured earth, confusingly renamed as erbia, and questioned the existence of the yellow earth. Marc Delafontaine adopted Berlin's nomenclature where erbia was the rose-coloured earth, but proved that the yellow earth also existed. At the prompting of Jean Charles Galissard de Marignac, he named the yellow earth terbia; thus Mosander's names were swapped from his original choices.
65	Terbium	1843	G. Mosander	1886	J.C.G. de Marignac	Mosander managed to split the old yttria into yttria proper and erbia, and later terbia too.
44	Ruthenium	1844	K. Claus	1844	K. Claus	Gottfried Wilhelm Osann thought that he found three new metals in Russian platinum samples in 1826, which he named polinium, pluranium, and ruthenium in 1828. But his results were questioned and he did not have enough quantities to isolate them, so he withdrew his claims in 1829. However, in 1844 Karl Karlovich Klaus confirmed that there was one new metal, and reused Osann's name "ruthenium".
55	Caesium	1860	R. Bunsen and R. Kirchhoff	1882	C. Setterberg	Bunsen and Kirchhoff were the first to suggest finding new elements by spectrum analysis. They discovered caesium by its two blue emission lines in a sample of Dürkheim mineral water. The pure metal was eventually isolated in 1882 by Setterberg.
37	Rubidium	1861	R. Bunsen and G. R. Kirchhoff	1863	R. Bunsen	Bunsen and Kirchhoff discovered it just a few months after caesium, by observing new spectral lines in the mineral lepidolite. The metal was isolated by Bunsen around 1863.
81	Thallium	1861	W. Crookes	1862	C.-A. Lamy	Shortly after the discovery of rubidium, Crookes found a new green line in a selenium sample; later that year, Lamy found the element to be metallic.
49	Indium	1863	F. Reich and T. Richter	1864	T. Richter	Reich and Richter first identified it in sphalerite by its bright indigo-blue spectroscopic emission line. Richter isolated the metal the next year.
2	Helium	1868	N. Lockyer	1895	W. Ramsay, T. Cleve, and N. Langlet	P. Janssen and Lockyer observed independently a yellow line in the solar spectrum that did not match any other element. However, only Lockyer made the correct conclusion that it was due to a new element. This was the first observation of a noble gas, located in the Sun. Years later after the isolation of argon on Earth, Ramsay, Cleve, and Langlet observed independently helium trapped in cleveite.
		1869	D. I. Mendeleev			Mendeleev arranges the 63 elements known at that time (omitting terbium, as chemists were unsure of its existence, and helium, as it was not found on Earth) into the first modern periodic table and correctly predicts several others.
31	Gallium	1875	P. E. L. de Boisbaudran	1878	P. E. L. de Boisbaudran and E. Jungfleisch	Boisbaudran observed on a pyrenea blende sample some emission lines corresponding to the eka-aluminium that was predicted by Mendeleev in 1871. He and Jungfleisch isolated the metal three years later by electrolysis.
70	Ytterbium	1878	J.C.G. de Marignac	1906	C. A. von Welsbach	On October 22, 1878, Marignac reported splitting terbia into two new earths, terbia proper and ytterbia.
67	Holmium	1878	J.-L. Soret and M. Delafontaine	1879	T. Cleve	Soret found it in samarskite and later, Per Teodor Cleve split Marignac's erbia into erbia proper and two new elements, thulium and holmium. Delafontaine's philippium turned out to be identical to what Soret found.
21	Scandium	1879	F. Nilson	1879	F. Nilson	Nilson split Marignac's ytterbia into pure ytterbia and a new element that matched Mendeleev's 1871 predicted eka-boron.
69	Thulium	1879	T. Cleve	1879	T. Cleve	Cleve split Marignac's erbia into erbia proper and two new elements, thulium and holmium.
62	Samarium	1879	P.E.L. de Boisbaudran	1879	P.E.L. de Boisbaudran	Boisbaudran noted a new earth in samarskite and named it samaria after the mineral.
64	Gadolinium	1880	J. C. G. de Marignac	1886	P.E.L. de Boisbaudran	Marignac initially observed the new earth in terbia, and later Boisbaudran obtained a pure sample from samarskite.
59	Praseodymium	1885	C. A. von Welsbach			Carl Auer von Welsbach discovered it in Mosander's didymia.
32	Germanium	1886	C. A. Winkler			In February 1886 Winkler found in argyrodite the eka-silicon that Mendeleev had predicted in 1871.
66	Dysprosium	1886	P.E.L. de Boisbaudran	1905	G. Urbain	De Boisbaudran found a new earth in erbia.
18	Argon	1894	Lord Rayleigh and W. Ramsay	1894	Lord Rayleigh and W. Ramsay	They discovered the gas by comparing the molecular weights of nitrogen prepared by liquefaction from air and nitrogen prepared by chemical means. It is the first noble gas to be isolated.
63	Europium	1896	E.-A. Demarçay	1901	E.-A. Demarçay	Demarçay found spectral lines of a new element in Lecoq's samarium, and separated this element several years later.
36	Krypton	1898	W. Ramsay and W. Travers	1898	W. Ramsay and W. Travers	On May 30, 1898, Ramsay separated a noble gas from liquid argon by difference in boiling point.
10	Neon	1898	W. Ramsay and W. Travers	1898	W. Ramsay and W. Travers	In June 1898 Ramsay separated a new noble gas from liquid argon by difference in boiling point.
54	Xenon	1898	W. Ramsay and W. Travers	1898	W. Ramsay and W. Travers	On July 12, 1898 Ramsay separated a third noble gas within three weeks, from liquid argon by difference in boiling point.
84	Polonium	1898	P. and M. Curie	1902	W. Marckwald	In an experiment done on July 13, 1898, the Curies noted an increased radioactivity in the uranium obtained from pitchblende, which they ascribed to an unknown element. Independently rediscovered and isolated in 1902 by Marckwald, who named it radiotellurium.
88	Radium	1898	P. and M. Curie	1902	M. Curie	The Curies reported on December 26, 1898, a new element different from polonium, which Marie later isolated from uraninite.
86	Radon	1899	E. Rutherford and R. B. Owens	1910	W. Ramsay and R. Whytlaw-Gray	Rutherford and Owens discovered a radioactive gas resulting from the radioactive decay of thorium, isolated later by Ramsay and Gray. In 1900, Friedrich Ernst Dorn discovered a longer-lived isotope of the same gas from the radioactive decay of radium. Since "radon" was first used to specifically designate Dorn's isotope before it became the name for the element, he is often mistakenly given credit for the latter instead of the former.
89	Actinium	1902	F. O. Giesel	1903	F. O. Giesel	Giesel obtained from pitchblende a substance that had properties similar to those of lanthanum and named it emanium. André-Louis Debierne had previously (in 1899 and 1900) reported the discovery of a new element actinium that was supposedly similar to titanium and thorium, which cannot have included much actual element 89. But by 1904, when Giesel and Debierne met, both had radiochemically pure element 89, and so Debierne has generally been given credit for the discovery.
71	Lutetium	1906	C. A. von Welsbach and G. Urbain	1906	C. A. von Welsbach	von Welsbach proved that the old ytterbium also contained a new element, which he named cassiopeium (he renamed the larger part of the old ytterbium to aldebaranium). Urbain also proved this at about the same time (von Welsbach's paper was published first, but Urbain sent his to the editor first), naming the new element lutetium and the old one neoytterbium (which later reverted back to ytterbium). However, Urbain's samples were very impure and only contained trace quantities of the new element. Despite this, his chosen name lutetium was adopted by the International Committee of Atomic Weights, whose membership included Urbain. The German Atomic Weights Commission adopted cassiopeium for the next forty years. Finally in 1949 IUPAC decided in favour of the name lutetium as it was more often used.
75	Rhenium	1908	M. Ogawa	1919	M. Ogawa	Masataka Ogawa found it in thorianite in 1908, but assigned it as element 43 and named it nipponium. (Elements 43 and 75 are in the same group of the periodic table.) Because of the erroneous assignment, and because some of his key results were published only in Japanese, his claim was not widely recognised. However, the optical emission spectrum described by Ogawa and the X-ray photographic plate for one of his samples match element 75, and his claim has thus been rehabilitated in much of the modern literature. In 1925 Walter Noddack, Ida Eva Tacke and Otto Berg announced its separation from gadolinite, identified it correctly as element 75, and gave it the present name.
91	Protactinium	1913	O. H. Göhring and K. Fajans	1927	A. von Grosse	The two obtained the first isotope of this element, 234mPa, that had been predicted by Mendeleev in 1871 as a member of the natural decay of 238U: they named it brevium. A longer-lived isotope 231Pa was found in 1918 by Otto Hahn and Lise Meitner, and was named by them protoactinium: since it is longer-lived, it gave the element its name. Protoactinium was changed to protactinium in 1949. Originally isolated in 1900 by William Crookes, who nevertheless did not recognize that it was a new element.
72	Hafnium	1922	D. Coster and G. von Hevesy	1922	D. Coster and G. von Hevesy	Georges Urbain claimed to have found the element in rare-earth residues, while Vladimir Vernadsky independently found it in orthite. Neither claim was confirmed due to World War I, and neither could be confirmed later, as the chemistry they reported does not match that now known for hafnium. After the war, Coster and Hevesy found it by X-ray spectroscopic analysis in Norwegian zircon. Hafnium was the last stable element to be discovered (noting however the difficulties regarding the discovery of rhenium).
43	Technetium	1937	C. Perrier and E. Segrè	1937	C. Perrier & E. Segrè	The two discovered a new element in a molybdenum sample that was used in a cyclotron, the first element to be discovered by synthesis. It had been predicted by Mendeleev in 1871 as eka-manganese. In 1952, Paul W. Merrill found its spectral lines in S-type red giants. Minuscule trace quantities were finally found on Earth in 1962 by B. T. Kenna and Paul K. Kuroda: they isolated it from Belgian Congo pitchblende, where it occurs as a spontaneous fission product of uranium. The Noddacks (rediscoverers of rhenium) claimed to have discovered element 43 in 1925 as well and named it masurium (after Masuria), but their claims were disproven by Kuroda, who calculated that there cannot have been enough technetium in their samples to have enabled a true detection.
87	Francium	1939	M. Perey			Perey discovered it as a decay product of 227Ac. Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. Before Perey, it is likely that Stefan Meyer, Viktor F. Hess, and Friedrich Paneth had observed the decay of 227Ac to 223Fr in Vienna in 1914, but they could not follow up and secure their work because of the outbreak of World War I.
93	Neptunium	1940	E.M. McMillan and H. Abelson			Obtained by irradiating uranium with neutrons, it was the first transuranium element discovered. Shortly before that, Yoshio Nishina and Kenjiro Kimura discovered the uranium isotope 237U and found that it beta decays into 23793, but were unable to measure the activity of the element 93 product because its half-life was too long. McMillan and Abelson succeeded because they used 239U, as 23993 has a much shorter half-life. McMillan and Abelson found that 23993 itself undergoes beta decay and must produce an isotope of element 94, but the quantities they used were not enough to isolate and identify element 94 along with 93. Natural traces were found in Belgian Congo pitchblende by D. F. Peppard et al. in 1952.
85	Astatine	1940	D. R. Corson, K. R. MacKenzie and E. Segrè			Obtained by bombarding bismuth with alpha particles. In 1943, Berta Karlik and Traude Bernert found it in nature; due to World War II, they were initially unaware of Corson et al.'s results. Horia Hulubei and Yvette Cauchois had previously claimed its discovery as a natural radioelement from 1936, naming it dor: they likely did have the isotope 218At, and probably did have enough sensitivity to distinguish its spectral lines. But they could not chemically identify their discovery, and their work was doubted because of an earlier false claim by Hulubei to having discovered element 87.
94	Plutonium	1941	Glenn T. Seaborg, Arthur C. Wahl, W. Kennedy and E.M. McMillan			Prepared by bombardment of uranium with deuterons. Seaborg and Morris L. Perlman then found it as traces in natural Canadian pitchblende in 1941–1942, though this work was kept secret until 1948.
96	Curium	1944	Glenn T. Seaborg, Ralph A. James and Albert Ghiorso			Prepared by bombarding plutonium with alpha particles during the Manhattan Project
95	Americium	1944	G. T. Seaborg, R. A. James, O. Morgan and A. Ghiorso			Prepared by irradiating plutonium with neutrons during the Manhattan Project.
61	Promethium	1945	Charles D. Coryell, Jacob A. Marinsky, and Lawrence E. Glendenin	1945	Charles D. Coryell, Jacob A. Marinsky, and Lawrence E. Glendenin	It was probably first prepared at the Ohio State University in 1942 by bombarding neodymium and praseodymium with neutrons, but separation of the element could not be carried out. Isolation was performed under the Manhattan Project in 1945. Found on Earth in trace quantities by Olavi Erämetsä in 1965; so far, promethium is the most recent element to have been found on Earth.
97	Berkelium	1949	G. Thompson, A. Ghiorso and G. T. Seaborg (University of California, Berkeley)			Created by bombardment of americium with alpha particles.
98	Californium	1950	S. G. Thompson, K. Street, Jr., A. Ghiorso and G. T. Seaborg (University of California, Berkeley)			Bombardment of curium with alpha particles.
99	Einsteinium	1952	A. Ghiorso et al. (Argonne Laboratory, Los Alamos Laboratory and University of California, Berkeley)	1952		Formed in the first thermonuclear explosion in November 1952, by irradiation of uranium with neutrons; kept secret for several years.
100	Fermium	1953	A. Ghiorso et al. (Argonne Laboratory, Los Alamos Laboratory and University of California, Berkeley)			Formed in the first thermonuclear explosion in November 1952, by irradiation of uranium with neutrons; first identified in early 1953; kept secret for several years.
101	Mendelevium	1955	A. Ghiorso, G. Harvey, G. R. Choppin, S. G. Thompson and G. T. Seaborg (Berkeley Radiation Laboratory)			Prepared by bombardment of einsteinium with alpha particles.
103	Lawrencium	1961	A. Ghiorso, T. Sikkeland, E. Larsh and M. Latimer (Berkeley Radiation Laboratory)			First prepared by bombardment of californium with boron atoms.
102	Nobelium	1966	E. D. Donets, V. A. Shchegolev and V. A. Ermakov (JINR in Dubna)			First prepared by bombardment of uranium with neon atoms
104	Rutherfordium	1969	A. Ghiorso et al. (Berkeley Radiation Laboratory) and I. Zvara et al. (JINR in Dubna)			Prepared by bombardment of californium with carbon atoms by Albert Ghiorso's team and by bombardment of plutonium with neon atoms by Zvara's team.
105	Dubnium	1970	A. Ghiorso et al. (Berkeley Radiation Laboratory) and V. A. Druin et al. (JINR in Dubna)			Prepared by bombardment of californium with nitrogen atoms by Ghiorso's team and by bombardment of americium with neon atoms by Druin's team.
106	Seaborgium	1974	A. Ghiorso et al. (Berkeley Radiation Laboratory)			Prepared by bombardment of californium with oxygen atoms.
107	Bohrium	1981	G.Münzenberg et al. (GSI in Darmstadt)			Obtained by bombarding bismuth with chromium.
109	Meitnerium	1982	G. Münzenberg, P. Armbruster et al. (GSI in Darmstadt)			Prepared by bombardment of bismuth with iron atoms.
108	Hassium	1984	G. Münzenberg, P. Armbruster et al. (GSI in Darmstadt)			Prepared by bombardment of lead with iron atoms
110	Darmstadtium	1994	S. Hofmann et al. (GSI in Darmstadt)			Prepared by bombardment of lead with nickel
111	Roentgenium	1994	S. Hofmann et al. (GSI in Darmstadt)			Prepared by bombardment of bismuth with nickel
112	Copernicium	1996	S. Hofmann et al. (GSI in Darmstadt)			Prepared by bombardment of lead with zinc.
114	Flerovium	1999	Y. Oganessian et al. (JINR in Dubna)			Prepared by bombardment of plutonium with calcium. It may have already been found at Dubna in 1998, but that result has not been confirmed.
116	Livermorium	2000	Y. Oganessian et al. (JINR in Dubna)			Prepared by bombardment of curium with calcium
118	Oganesson	2002	Y. Oganessian et al. (JINR in Dubna)			Prepared by bombardment of californium with calcium
115	Moscovium	2003	Y. Oganessian et al. (JINR in Dubna)			Prepared by bombardment of americium with calcium
113	Nihonium	2003–2004	Y. Oganessian et al. (JINR in Dubna) and K. Morita et al. (RIKEN in Wako, Japan)			Prepared by decay of moscovium by Oganessian's team and bombardment of bismuth with zinc by Morita's team. Both teams began their experiments in 2003; Oganessian's team detected its first atom in 2003, but Morita's only in 2004. However, both teams published in 2004.
117	Tennessine	2009	Y. Oganessian et al. (JINR in Dubna)			Prepared by bombardment of berkelium with calcium

Gallery

See also

• History of the periodic table
• Periodic table
• Extended periodic table
• The Mystery of Matter: Search for the Elements (2014/2015 PBS film)
• Transfermium Wars