iii Los Alamos National Laboratory, Chemistry Division Periodic Table of the Elements Group 1 18 Period 1 1 H Hydrogen 1.008 2 1 H Hydrogen 1.008 13 14 15 16 17 2 He Helium 4.003 2 3 Li Lithium 6.941 4 Be Beryllium 9.012 5 B Boron 10.811 6 C Carbon 12.011 7 N Nitrogen 14.007 8 O Oxygen 15.999 9 F Fluorine 18.998 10 Ne Neon 20.180 3 11 Na Sodium 22.990 12 Mg Magnesium 24.305 3 4 5 6 7 8 9 10 11 12 13 Al Aluminum 26.982 14 Si Silicon 28.086 15 P Phosphorus 30.974 16 S Sulfur 32.065 17 Cl Chlorine 35.453 18 Ar Argon 39.948 4 19 K Potassium 39.098 20 Ca Calcium 40.078 21 Sc Scandium 44.956 22 Ti Ti tanium 47.867 23 V Vanadium 50.942 24 Cr Chromium 51.996 25 Mn Manganese 54.938 26 Fe Iron 55.845 27 Co Cobalt 58.933 28 Ni Nickel 58.693 29 Cu Copper 63.546 30 Zn Zinc 65.38 31 Ga Gallium 69.723 32 Ge Germanium 72.64 33 As Arsenic 74.922 34 Se Selenium 78.96 35 Br Bromine 79.904 36 Kr Krypton 83.798 5 37 Rb Rubidium 85.468 38 Sr Strontium 87.62 39 Y Yttrium 88.906 40 Zr Zirconium 91.224 41 Nb Niobium 92.906 42 Mo Molybdenum 95.96 43 Tc Technetium (98) 44 Ru Ruthenium 101.07 45 Rh Rhodium 102.91 46 Pd Palladium 106.42 47 Ag Silver 107.87 48 Cd Cadmium 112.41 49 In Indium 114.82 50 Sn Ti n 118.71 51 Sb Antimony 121.76 52 Te Tellurium 127.60 53 I Iodine 126.90 54 Xe Xenon 131.29 6 55 Cs Cesium 132.91 56 Ba Barium 137.32 57-71 Lanthanides 72 Hf Hafnium 178.49 73 Ta Tantalum 180.95 74 W Tungsten 183.84 75 Re Rhenium 186.21 76 Os Osmium 190.23 77 Ir Iridium 192.22 78 Pt Platinum 195.08 79 Au Gold 196.97 80 Hg Mercury 200.59 81 Tl Thallium 204.38 82 Pb Lead 207.2 83 Bi Bismuth 208.98 84 Po Polonium (209) 85 At Astatine (210) 86 Rn Radon (222) 7 87 Fr Francium (223) 88 Ra Radium (226) 89-103 Actinides 104 Rf Rutherfordium (263) 105 Db Dubnium (268) 106 Sg Seaborgium (271) 107 Bh Bohrium (270) 108 Hs Hassium (270) 109 Mt Meitnerium (278) 110 Ds Darmstadtium (281) 111 Rg Roentgenium (281) 112 Cn Copernicium (285) 113 Nh Nihonium (286) 114 Fl Flerovium (289) 115 Mc Moscovium (289) 116 Lv Livermorium (293) 117 Ts Tennessine (294) 118 Og Oganesson (294) 57 La Lanthanum 138.91 58 Ce Cerium 140.11 59 Pr Praseodymium 140.91 60 Nd Neodymium 144.24 61 Pm Promethium (145) 62 Sm Samarium 150.36 63 Eu Europium 151.96 64 Gd Gadolinium 157.25 65 Tb Terbium 158.93 66 Dy Dysprosium 162.50 67 Ho Holmium 164.93 68 Er Erbium 167.26 69 Tm Thulium 168.93 70 Yb Ytterbium 173.05 71 Lu Lutetium 174.97 89 Ac Actinium (227) 90 Th Thorium 232.04 91 Pa Protactinium 231.04 92 U Uranium 238.03 93 Np Neptunium (237) 94 Pu Plutonium (244) 95 Am Americium (243) 96 Cm Curium (247) 97 Bk Berkelium (247) 98 Cf Californium (251) 99 Es Einsteinium (252) 100 Fm Fermium (257) 101 Md Mendelevium (258) 102 No Nobelium (259) 103 Lr Lawrencium (262) slatem noitisnarT sedinitcA sedinahtnaL slatem htrae enilaklA slatem ilaklA Other metals Metalloids Other nonmetal s H alogen s Noble gases Chemical symbol Chemical name Atomic weight Atomic number