2
He
Helium
4.0026022
He
Helium
4.0026022
noble gas
Appearance: colorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field
Boiling Point: 4.222
Density: 0.1786
Phase: Gas
Discovered by: Pierre Janssen
Summary: Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among all the elements.
10
Ne
Neon
20.17976
Ne
Neon
20.17976
noble gas
Appearance: colorless gas exhibiting an orange-red glow when placed in a high voltage electric field
Boiling Point: 27.104
Density: 0.9002
Phase: Gas
Discovered by: Morris Travers
Summary: Neon is a chemical element with symbol Ne and atomic number 10. It is in group 18 (noble gases) of the periodic table. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air.
18
Ar
Argon
39.9481
Ar
Argon
39.9481
noble gas
Appearance: colorless gas exhibiting a lilac/violet glow when placed in a high voltage electric field
Boiling Point: 87.302
Density: 1.784
Phase: Gas
Discovered by: Lord Rayleigh
Summary: Argon is a chemical element with symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most common gas in the Earth's atmosphere, at 0.934% (9,340 ppmv), making it over twice as abundant as the next most common atmospheric gas, water vapor (which averages about 4000 ppmv, but varies greatly), and 23 times as abundant as the next most common non-condensing atmospheric gas, carbon dioxide (400 ppmv), and more than 500 times as abundant as the next most common noble gas, neon (18 ppmv).
36
Kr
Krypton
83.7982
Kr
Krypton
83.7982
noble gas
Appearance: colorless gas, exhibiting a whitish glow in a high electric field
Boiling Point: 119.93
Density: 3.749
Phase: Gas
Discovered by: William Ramsay
Summary: Krypton (from Greek:κρυπτός kryptos "the hidden one") is a chemical element with symbol Kr and atomic number 36. It is a member of group 18 (noble gases) elements. A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere, is isolated by fractionally distilling liquefied air, and is often used with other rare gases in fluorescent lamps.
54
Xe
Xenon
131.2936
Xe
Xenon
131.2936
noble gas
Appearance: colorless gas, exhibiting a blue glow when placed in a high voltage electric field
Boiling Point: 165.051
Density: 5.894
Phase: Gas
Discovered by: William Ramsay
Summary: Xenon is a chemical element with symbol Xe and atomic number 54. It is a colorless, dense, odorless noble gas, that occurs in the Earth's atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.
57-71
86
Rn
Radon
222
Rn
Radon
222
noble gas
Appearance: colorless gas, occasionally glows green or red in discharge tubes
Boiling Point: 211.5
Density: 9.73
Phase: Gas
Discovered by: Friedrich Ernst Dorn
Summary: Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as a decay product of radium. Its most stable isotope, 222Rn, has a half-life of 3.8 days.
89-103
118
Og
Oganesson
294
Og
Oganesson
294
unknown, predicted to be noble gas
Boiling Point: 350
Density: 4.95
Phase: Solid
Discovered by: Joint Institute for Nuclear Research
Summary: Oganesson is IUPAC's name for the transactinide element with the atomic number 118 and element symbol Og. It is also known as eka-radon or element 118, and on the periodic table of the elements it is a p-block element and the last one of the 7th period. Oganesson is currently the only synthetic member of group 18.
57
La
Lanthanum
138.905477
La
Lanthanum
138.905477
lanthanide
Appearance: silvery white
Boiling Point: 3737
Density: 6.162
Phase: Solid
Discovered by: Carl Gustaf Mosander
Summary: Lanthanum is a soft, ductile, silvery-white metallic chemical element with symbol La and atomic number 57. It tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It gave its name to the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table:it is also sometimes considered the first element of the 6th-period transition metals.
58
Ce
Cerium
140.1161
Ce
Cerium
140.1161
lanthanide
Appearance: silvery white
Boiling Point: 3716
Density: 6.77
Phase: Solid
Discovered by: Martin Heinrich Klaproth
Summary: Cerium is a chemical element with symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet Ceres (itself named after the Roman goddess of agriculture).
59
Pr
Praseodymium
140.907662
Pr
Praseodymium
140.907662
lanthanide
Appearance: grayish white
Boiling Point: 3403
Density: 6.77
Phase: Solid
Discovered by: Carl Auer von Welsbach
Summary: Praseodymium is a chemical element with symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is valued for its magnetic, electrical, chemical, and optical properties.
60
Nd
Neodymium
144.2423
Nd
Neodymium
144.2423
lanthanide
Appearance: silvery white
Boiling Point: 3347
Density: 7.01
Phase: Solid
Discovered by: Carl Auer von Welsbach
Summary: Neodymium is a chemical element with symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach.
61
Pm
Promethium
145
Pm
Promethium
145
lanthanide
Appearance: metallic
Boiling Point: 3273
Density: 7.26
Phase: Solid
Discovered by: Chien Shiung Wu
Named by: Isotopes of promethium
Summary: Promethium, originally prometheum, is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive; it is one of only two such elements that are followed in the periodic table by elements with stable forms, a distinction shared with technetium. Chemically, promethium is a lanthanide, which forms salts when combined with other elements.
62
Sm
Samarium
150.362
Sm
Samarium
150.362
lanthanide
Appearance: silvery white
Boiling Point: 2173
Density: 7.52
Phase: Solid
Discovered by: Lecoq de Boisbaudran
Summary: Samarium is a chemical element with symbol Sm and atomic number 62. It is a moderately hard silvery metal that readily oxidizes in air. Being a typical member of the lanthanide series, samarium usually assumes the oxidation state +3.
63
Eu
Europium
151.9641
Eu
Europium
151.9641
lanthanide
Boiling Point: 1802
Density: 5.264
Phase: Solid
Discovered by: Eugène-Anatole Demarçay
Summary: Europium is a chemical element with symbol Eu and atomic number 63. It was isolated in 1901 and is named after the continent of Europe. It is a moderately hard, silvery metal which readily oxidizes in air and water.
64
Gd
Gadolinium
157.253
Gd
Gadolinium
157.253
lanthanide
Appearance: silvery white
Boiling Point: 3273
Density: 7.9
Phase: Solid
Discovered by: Jean Charles Galissard de Marignac
Summary: Gadolinium is a chemical element with symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined (salt) form.
65
Tb
Terbium
158.925352
Tb
Terbium
158.925352
lanthanide
Appearance: silvery white
Boiling Point: 3396
Density: 8.23
Phase: Solid
Discovered by: Carl Gustaf Mosander
Summary: Terbium is a chemical element with symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.
66
Dy
Dysprosium
162.5001
Dy
Dysprosium
162.5001
lanthanide
Appearance: silvery white
Boiling Point: 2840
Density: 8.54
Phase: Solid
Discovered by: Lecoq de Boisbaudran
Summary: Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime.
67
Ho
Holmium
164.930332
Ho
Holmium
164.930332
lanthanide
Appearance: silvery white
Boiling Point: 2873
Density: 8.79
Phase: Solid
Discovered by: Marc Delafontaine
Summary: Holmium is a chemical element with symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare earth element. Holmium was discovered by Swedish chemist Per Theodor Cleve.
68
Er
Erbium
167.2593
Er
Erbium
167.2593
lanthanide
Appearance: silvery white
Boiling Point: 3141
Density: 9.066
Phase: Solid
Discovered by: Carl Gustaf Mosander
Summary: Erbium is a chemical element in the lanthanide series, with symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements on Earth. As such, it is a rare earth element which is associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden, where yttrium, ytterbium, and terbium were discovered.
69
Tm
Thulium
168.934222
Tm
Thulium
168.934222
lanthanide
Appearance: silvery gray
Boiling Point: 2223
Density: 9.32
Phase: Solid
Discovered by: Per Teodor Cleve
Summary: Thulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate (third-last) element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.
70
Yb
Ytterbium
173.0451
Yb
Ytterbium
173.0451
lanthanide
Boiling Point: 1469
Density: 6.9
Phase: Solid
Discovered by: Jean Charles Galissard de Marignac
Summary: Ytterbium is a chemical element with symbol Yb and atomic number 70. It is the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. However, like the other lanthanides, its most common oxidation state is +3, seen in its oxide, halides and other compounds.
71
Lu
Lutetium
174.96681
Lu
Lutetium
174.96681
lanthanide
Appearance: silvery white
Boiling Point: 3675
Density: 9.841
Phase: Solid
Discovered by: Georges Urbain
Summary: Lutetium is a chemical element with symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry, but not in moist air. It is considered the first element of the 6th-period transition metals and the last element in the lanthanide series, and is traditionally counted among the rare earths.
89
Ac
Actinium
227
Ac
Actinium
227
actinide
Boiling Point: 3500
Density: 10
Phase: Solid
Discovered by: Friedrich Oskar Giesel
Summary: Actinium is a radioactive chemical element with symbol Ac (not to be confused with the abbreviation for an acetyl group) and atomic number 89, which was discovered in 1899. It was the first non-primordial radioactive element to be isolated. Polonium, radium and radon were observed before actinium, but they were not isolated until 1902.
90
Th
Thorium
232.03774
Th
Thorium
232.03774
actinide
Appearance: silvery, often with black tarnish
Boiling Point: 5061
Density: 11.724
Phase: Solid
Discovered by: Jöns Jakob Berzelius
Summary: Thorium is a chemical element with symbol Th and atomic number 90. A radioactive actinide metal, thorium is one of only two significantly radioactive elements that still occur naturally in large quantities as a primordial element (the other being uranium). It was discovered in 1828 by the Norwegian Reverend and amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jakob Berzelius, who named it after Thor, the Norse god of thunder.
91
Pa
Protactinium
231.035882
Pa
Protactinium
231.035882
actinide
Appearance: bright, silvery metallic luster
Boiling Point: 4300
Density: 15.37
Phase: Solid
Discovered by: William Crookes
Named by: Otto Hahn
Summary: Protactinium is a chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume +4 and even +2 or +3 states.
92
U
Uranium
238.028913
U
Uranium
238.028913
actinide
Boiling Point: 4404
Density: 19.1
Phase: Solid
Discovered by: Martin Heinrich Klaproth
Summary: Uranium is a chemical element with symbol U and atomic number 92. It is a silvery-white metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons.
93
Np
Neptunium
237
Np
Neptunium
237
actinide
Appearance: silvery metallic
Boiling Point: 4447
Density: 20.45
Phase: Solid
Discovered by: Edwin McMillan
Summary: Neptunium is a chemical element with symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus.
94
Pu
Plutonium
244
Pu
Plutonium
244
actinide
Appearance: silvery white, tarnishing to dark gray in air
Boiling Point: 3505
Density: 19.816
Phase: Solid
Discovered by: Glenn T. Seaborg
Summary: Plutonium is a transuranic radioactive chemical element with symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states.
95
Am
Americium
243
Am
Americium
243
actinide
Appearance: silvery white
Boiling Point: 2880
Density: 12
Phase: Solid
Discovered by: Glenn T. Seaborg
Summary: Americium is a radioactive transuranic chemical element with symbol Am and atomic number 95. This member of the actinide series is located in the periodic table under the lanthanide element europium, and thus by analogy was named after the Americas. Americium was first produced in 1944 by the group of Glenn T.Seaborg from Berkeley, California, at the metallurgical laboratory of University of Chicago.
96
Cm
Curium
247
Cm
Curium
247
actinide
Appearance: silvery metallic, glows purple in the dark
Boiling Point: 3383
Density: 13.51
Phase: Solid
Discovered by: Glenn T. Seaborg
Summary: Curium is a transuranic radioactive chemical element with symbol Cm and atomic number 96. This element of the actinide series was named after Marie and Pierre Curie – both were known for their research on radioactivity. Curium was first intentionally produced and identified in July 1944 by the group of Glenn T. Seaborg at the University of California, Berkeley.
97
Bk
Berkelium
247
Bk
Berkelium
247
actinide
Appearance: silvery
Boiling Point: 2900
Density: 14.78
Phase: Solid
Discovered by: Lawrence Berkeley National Laboratory
Summary: Berkelium is a transuranic radioactive chemical element with symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the University of California Radiation Laboratory where it was discovered in December 1949.
98
Cf
Californium
251
Cf
Californium
251
actinide
Appearance: silvery
Boiling Point: 1743
Density: 15.1
Phase: Solid
Discovered by: Lawrence Berkeley National Laboratory
Summary: Californium is a radioactive metallic chemical element with symbol Cf and atomic number 98. The element was first made in 1950 at the University of California Radiation Laboratory in Berkeley, by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium).
99
Es
Einsteinium
252
Es
Einsteinium
252
actinide
Appearance: silver-colored
Boiling Point: 1269
Density: 8.84
Phase: Solid
Discovered by: Lawrence Berkeley National Laboratory
Summary: Einsteinium is a synthetic element with symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide. Einsteinium was discovered as a component of the debris of the first hydrogen bomb explosion in 1952, and named after Albert Einstein.
100
Fm
Fermium
257
Fm
Fermium
257
actinide
Density: null
Phase: Solid
Discovered by: Lawrence Berkeley National Laboratory
Summary: Fermium is a synthetic element with symbol Fm and atomic number 100. It is a member of the actinide series. It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared.
101
Md
Mendelevium
258
Md
Mendelevium
258
actinide
Density: null
Phase: Solid
Discovered by: Lawrence Berkeley National Laboratory
Summary: Mendelevium is a synthetic element with chemical symbol Md (formerly Mv) and atomic number 101. A metallic radioactive transuranic element in the actinide series, it is the first element that currently cannot be produced in macroscopic quantities through neutron bombardment of lighter elements. It is the antepenultimate actinide and the ninth transuranic element.
102
No
Nobelium
259
No
Nobelium
259
actinide
Density: null
Phase: Solid
Discovered by: Joint Institute for Nuclear Research
Summary: Nobelium is a synthetic chemical element with symbol No and atomic number 102. It is named in honor of Alfred Nobel, the inventor of dynamite and benefactor of science. A radioactive metal, it is the tenth transuranic element and is the penultimate member of the actinide series.
103
Lr
Lawrencium
266
Lr
Lawrencium
266
actinide
Density: null
Phase: Solid
Discovered by: Lawrence Berkeley National Laboratory
Summary: Lawrencium is a synthetic chemical element with chemical symbol Lr (formerly Lw) and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and is also the final member of the actinide series.