Name Symbol Atomic Atomic Discoverer Country Date
number weight
Actinium Ac 89 227.028 Andre Debierne France 1899
Aluminum Al 13 26.9815 Hans Christian Oersted Denmark 1825
Americium Am 95 [243] G. T. Seaborg; R. A. United 1945
James; L. O. Morgan; States
A. Ghiorso
Antimony Sb 51 121.75 Unknown; name applied
to pure element in
France in 1787
Argon Ar 18 39.948 Sir William Ramsay; Britain 1894
Baron Rayleigh
Arsenic As 33 74.9216 Uncertain; often
credited to Albertus
Magnus in Germany
about 1250
Astatine At 85 [210] D. R. Corson; K. R. United 1940
MacKenzie; E. Segre States
Barium Ba 56 137.33 Sir Humphry Davy Britain 1808
Berkelium Bk 97 [247] G. T. Seaborg; S. G. United 1949
Thompson; A. Ghiorso States
Beryllium Be 4 9.0128 Friedrich Wohler; A. Germany; 1828
A. Bussy France
Bismuth Bi 83 208.980 Unknown; preparation
described in Germany
in 1556
Boron B 5 10.81 H. Davy; J. L. Gay- Britain; 1808
Lussac; L. J. France
Thenard
Bromine Br 35 79.904 Antoine J. Balard; France; 1826
Carl J. Lowig Germany
Cadmium Cd 48 112.41 Friedrich Stromeyer Germany 1817
Calcium Ca 20 40.08 Sir Humphry Davy Britain 1808
Californium Cf 98 [251] G. T. Seaborg; S. G. United 1950
Thompson; A. States
Ghiorso; K. Street, Jr
Carbon C 6 12.011 Known to ancients
Cerium Ce 58 140.12 W. von Hisinger; J. Sweden; 1803
Berzelius; M. Germany
Klaproth
Cesium Cs 55 132.905 Gustav Kirchhoff, Germany 1860
Robert Bunsen
Chlorine Cl 17 35.453 Carl Wilhelm Scheele Sweden 1774
Chromium Cr 24 51.996 Louis Vauquelin France 1797
Cobalt Co 27 58.9332 Georg Brandt Sweden Late 1730s
Copper Cu 29 63.546 Known to ancients
Curium Cm 96 [247] G. T. Seaborg; R. A. United 1944
James; A. Ghiorso States
Dysprosium Dy 66 162.50 Paul Emile Lecoq de France 1886
Boisbaudran
Einsteinium Es 99 [252] Argonne; Los Alamos; United 1952
Berkeley States
Element 104 none 104 [261] Joint Institute for Russia 1969-1970
Nuclear Research
Lawrence Berkeley United
Laboratory States
Element 105 none 105 [263] Joint Institute for Russia 1970-1971
Nuclear Research
Lawrence Berkeley United
Laboratory States
Element 106 none 106 [266] Lawrence Berkeley United 1974
Laboratory States
Lawrence Livermore United 1974
National Laboratory States
Element 107 none 107 [264] Heavy Ion Research Germany 1981
Center
Element 108 none 108 [267] Heavy Ion Research Germany 1984
Center
Element 109 none 109 [268] Heavy Ion Research Germany 1982
Center
Erbium Er 68 167.26 Carl Mosander Sweden 1843
Europium Eu 63 151.96 Eugene Demarcay France 1901
Fermium Fm 100 [257] Argonne; Los Alamos; United 1953
Univerity of States
California
Fluorine F 9 18.9984 Henri Moissan France 1886
Francium Fr 87 [223] Marguerite Perey France 1939
Gadolinium Gd 64 157.25 Jean de Marignac Switzerland 1880
Gallium Ga 31 69.72 Paul Emile Lecoq de France 1875
Boisbaudran
Germanium Ge 32 72.59 Clemens Winkler Germany 1886
Gold Au 79 196.967 Known to ancients
Hafnium Hf 72 178.49 Dirk Coster; Georg von Denmark 1923
Hevesy
Helium He 2 4.00260 Sir William Ramsay; Britain; 1895
Nils Langlet; P. T. Sweden
Cleve
Holmium Ho 67 164.930 J. L. Soret Switzerland 1878
Hydrogen H 1 1.0079 Henry Cavendish Britain 1766
Indium In 49 114.82 Ferdinand Reich; H. Germany 1863
Richter
Iodine I 53 126.905 Bernard Courtois France 1811
Iridium Ir 77 192.22 Smithson Tennant Britain 1804
Iron Fe 26 55.847 Known to ancients
Krypton Kr 36 83.80 Sir William Ramsay; M. Britain 1898
W. Travers
Lanthanum La 57 138.906 Carl Mosander Sweden 1839
Lawrencium Lr 103 262 Joint Institute for Russia 1961
Nuclear Research
Lawrence Berkeley United
Laboratory States
Lead Pb 82 207.2 Known to ancients
Lithium Li 3 6.941 Johann Arfvedson Sweden 1817
Lutetium Lu 71 174.967 Georges Urbain France 1907
Magnesium Mg 12 24.305 Sir Humphry Davy Britain 1808
Manganese Mn 25 54.9380 Johan Gahn Sweden 1774
Mendelevium Md 101 [258] Lawrence Berkeley United 1958
Laboratory States
Mercury Hg 80 200.59 Known to ancients
Molybdenum Mo 42 95.94 Carl Wilhelm Scheele Sweden 1778
Neodymium Nd 60 144.24 C. F. Auer von Austria 1885
Welsbach
Neon Ne 10 20.179 Sir William Ramsay; M. Britain 1898
W. Travers
Neptunium Np 93 237.048 E. M. McMillan; P. H. United 1940
Abelson States
Nickel Ni 28 58.69 Axel Cronstedt Sweden 1751
Niobium Nb 41 92.9064 Charles Hatchett Britain 1801
Nitrogen N 7 14.0067 Daniel Rutherford Britain 1772
Nobelium No 102 [259] Joint Institute for Russia 1966
Nuclear Research
Osmium Os 76 190.2 Smithson Tennant Britain 1804
Oxygen O 8 15.9994 Joseph Priestley; Carl Britain; 1774
Wilhelm Scheele Sweden
Palladium Pd 46 106.42 William Wollaston Britain 1803
Phosphorus P 15 30.9738 Hennig Brand Germany 1669
Platinum Pt 78 195.08 Julius Scaliger Italy 1557
Plutonium Pu 94 [244] G. T. Seaborg; J. W. United 1940
Kennedy; E. M. States
McMillan; A. C. Wahl
Polonium Po 84 [209] Pierre and Marie Curie France 1898
Potassium K 19 39.0983 Sir Humphry Davy Britain 1807
Praseodymium Pr 59 140.908 C. F. Auer von Austria 1885
Welsbach
Promethium Pm 61 [145] J. A. Marinsky; United 1945
Lawrence E. States
Glendenin; Charles
D. Coryell
Protactinium Pa 91 231.036 Otto Hahn; Lise Germany; 1917
Meitner; Frederick Britain
Soddy; John Cranston
Radium Ra 88 226.025 Pierre and Marie Curie France 1898
Radon Rn 86 [222] Friedrich Ernst Dorn Germany 1900
Rhenium Re 75 186.207 Walter Noddack; Ida Germany 1925
Tacke; Otto Berg
Rhodium Rh 45 102.906 William Wollaston Britain 1803
Rubidium Rb 37 85.4678 R. Bunsen; G. Germany 1861
Kirchhoff
Ruthenium Ru 44 101.07 Karl Klaus Russia 1844
Samarium Sm 62 150.36 Paul Emile Lecoq de France 1879
Boisbaudran
Scandium Sc 21 44.9559 Lars Nilson Sweden 1879
Selenium Se 34 78.96 Jons Berzelius Sweden 1817
Silicon Si 14 28.0855 Jons Berzelius Sweden 1823
Silver Ag 47 107.868 Known to ancients
Sodium Na 11 22.9898 Sir Humphry Davy Britain 1807
Strontium Sr 38 87.62 A. Crawford Britain 1790
Sulphur S 16 32.06 Known to ancients
Tantalum Ta 73 180.948 Anders Ekeberg Sweden 1802
Technetium Tc 43 [98] Carlo Perrier; Emilio Italy 1937
Segre
Tellurium Te 52 127.60 Franz Muller von Romania 1782
Reichenstein
Terbium Tb 65 158.925 Carl Mosander Sweden 1843
Thallium Tl 81 204.383 Sir William Crookes Britain 1861
Thorium Th 90 232.038 Jons Berzelius Sweden 1828
Thulium Tm 69 168.934 Per Theodor Cleve Sweden 1879
Tin Sn 50 118.71 Known to ancients
Titanium Ti 22 47.88 William Gregor Britain 1791
Tungsten W 74 183.85 Fausto and Juan Jose Spain 1783
de Elhuyar
Uranium U 92 238.029 Martin Klaproth Germany 1789
Vanadium V 23 50.9415 Nils Sefstrom Sweden 1830
Xenon Xe 54 131.29 Sir William Ramsay; M. Britain 1898
W. Travers
Ytterbium Yb 70 173.04 Jean de Marignac Switzerland 1878
Yttrium Y 39 88.9059 Johann Gadolin Finland 1794
Zinc Zn 30 65.39 Andreas Marggraf Germany 1746
Zirconium Zr 40 91.224 Martin Klaproth Germany 1789
