ExplanAtomic Number Atomic Mass Chemical Element Name Symbol Discovery (Year) GROUP1 1.0079 Hydrogen H 1776 12 4.0026 Helium He 1895 183 6.941 Lithium Li 1817 14 9.0122 Beryllium Be 1797 25 10.811 Boron B 1808 136 12.0107 Carbon C Ancient 147 14.0067 Nitrogen N 1772 158 15.9994 Oxygen O 1774 169 18.9984 Fluorine F 1886 1710 20.1797 Neon Ne 1898 1811 22.9897 Sodium Na 1807 112 24.305 Magnesium Mg 1755 213 26.9815 Aluminum Al 1825 1314 28.0855 Silicon Si 1824 1415 30.9738 Phosphorus P 1669 1516 32.065 Sulfur S Ancient 1617 35.453 Chlorine Cl 1774 1718 39.948 Argon Ar 1894 1819 39.0983 Potassium K 1807 120 40.078 Calcium Ca 1808 221 44.9559 Scandium Sc 1879 322 47.867 Titanium Ti 1791 423 50.9415 Vanadium V 1830 524 51.9961 Chromium Cr 1797 625 54.938 Manganese Mn 1774 726 55.845 Iron Fe Ancient 827 58.9332 Cobalt Co 1735 928 58.6934 Nickel Ni 1751 1029 63.546 Copper Cu Ancient 1130 65.39 Zinc Zn Ancient 1231 69.723 Gallium Ga 1875 1332 72.64 Germanium Ge 1886 1433 74.9216 Arsenic As Ancient 1534 78.96 Selenium Se 1817 1635 79.904 Bromine Br 1826 1736 83.8 Krypton Kr 1898 1837 85.4678 Rubidium RB 1861 138 87.62 Strontium Sr 1790 239 88.9059 Yttrium Y 1794 340 91.224 Zirconium Zr 1789 441 92.9064 Niobium Nb 1801 542 95.94 Molybdenum Mo 1781 643 98 Technetium Tc 1937 744 101.07 Ruthenium Ru 1844 845 102.9055 Rhodium Rh 1803 946 106.42 Palladium Pd 1803 1047 107.8682 Silver Ag Ancient 1148 112.411 Cadmium Cd 1817 1249 114.818 Indium In 1863 1350 118.71 Tin Sn Ancient 1451 121.76 Antimony Sb Ancient 1552 127.6 Tellurium Te 1783 1653 126.9045 Iodine In 1811 1754 131.293 Xenon Xe 1898 1855 132.9055 Cesium Cs 1860 156 137.327 Barium Ba 1808 257 138.9055 Lanthanum La 1839 358 140.116 Cerium Ce 1803 10159 140.9077 Praseodymium Pr 1885 10160 144.24 Neodymium Nd 1885 10161 145 Promethium Pm 1945 10162 150.36 Samarium Sm 1879 10163 151.964 Europium Eu 1901 10164 157.25 Gadolinium Gd 1880 10165 158.9253 Terbium Tb 1843 10166 162.5 Dysprosium Dy 1886 10167 164.9303 Holmium Ho 1867 10168 167.259 ERBIUM Er 1842 10169 168.9342 Thulium Tm 1879 10170 173.04 Ytterbium Yb 1878 10171 174.967 Lutetium Lu 1907 10172 178.49 Hafnium Hf 1923 473 180.9479 Tantalum Ta 1802 574 183.84 Tungsten W 1783 675 186.207 Rhenium Re 1925 776 190.23 Osmium Os 1803 877 196.9665 Iridium Ir Ancient 1178 192.217 Platinum Pt 1803 979 195.078 Gold Au 1735 1080 200.59 Mercury Hg Ancient 1281 204.3833 Thallium Tl 1861 1382 207.2 Lead Pb Ancient 1483 208.9804 Bismuth Bi Ancient 1584 209 Polonium Po 1898 1685 210 Astatine At 1940 1786 222 Radon Rn 1900 1887 223 Francium Fr 1939 188 226 Radium Ra 1898 289 227 Actinium Ac 1899 390 232.0381 Thorium Th 1829 10291 231.0359 Protactinium Pa 1913 10292 238.0289 Uranium U 1789 10293 237 NEPTUNIUM Np 1940 10294 244 Plutonium Pu 1940 10295 243 Americium Am 1944 10296 247 Curium Cm 1944 10297 247 Berkelium Bk 1949 10298 251 Californium Cf 1950 10299 252 Einsteinium Es 1952 102100 257 Fermium Fm 1952 102101 258 Mendelevium Md 1955 102102 259 Nobelium No 1958 102103 262 Lawrencium Lr 1961 102104 261 Rutherfordium Rf 1964 4105 262 Dubnium Db 1967 5106 266 Seaborgium Sg 1974 6107 264 Bohrium Bh 1981 7108 277 Hassium Hs 1984 8109 268 Meitnerium Mt 1982 9110 261.9 Darmstadtium Ds 1994 10111 271.8 Roentgenium Rg 1994 11112 285 Copernicium Cn 1996 12113 286 Ununtrium Uut 2003 13114 289 Flerovium Fl 1998 14115 288 Ununpentium Uup 2010 15116 293 Livermorium Lv 2000 16117 260.9 Ununseptium Uus 2010 17118 294 Ununoctiumation: