IUPAC Periodic Table of the Elements 1 18 2 1 He H helium hydrogen 1.008 [1.0078, 1.0082] 2 3 4 Li lithium Key: atomic number Be beryllium 11 Na magnesium [24.304, 24.307] 24.305 19 K 20 Ca 17 5 6 7 8 9 21 nitrogen O oxygen 10.81 12.011 14.007 15.999 [12.009, 12.012] [14.006, 14.008] [15.999, 16.000] 13 Sc carbon N [10.806, 10.821] Al 3 C conventional atomic weight 12 22.990 16 standard atomic weight Mg sodium 15 boron name 9.0122 14 B Symbol 6.94 [6.938, 6.997] 13 4 22 Ti 5 23 V 6 24 Cr 7 25 8 26 9 27 Mn Fe iron cobalt 55.845(2) 58.933 potassium calcium scandium titanium vanadium chromium manganese 39.098 40.078(4) 44.956 47.867 50.942 51.996 54.938 Co 10 28 Ni 11 29 12 30 14 Si aluminium silicon 26.982 [28.084, 28.086] 15 P 31 32 Ge 10 F Ne 18.998 20.180 fluorine 17 Cl 18 Ar sulfur 32.06 35.45 39.95 30.974 [32.059, 32.076] [35.446, 35.457] [39.792, 39.963] 33 As 34 Se chlorine neon phosphorus 28.085 Ga 16 S 4.0026 35 nickel Cu copper Zn Br zinc gallium germanium arsenic selenium bromine 58.693 63.546(3) 65.38(2) 69.723 72.630(8) 74.922 78.971(8) [79.901, 79.907] 52 53 argon 36 Kr krypton 79.904 37 Rb 38 Sr 39 Y 40 Zr 41 Nb 42 Mo rubidium strontium yttrium zirconium niobium molybdenum 85.468 87.62 88.906 91.224(2) 92.906 95.95 55 56 57-71 72 73 74 Cs Ba caesium barium 132.91 137.33 lanthanoids Hf Ta W 43 Tc technetium 75 Re 44 Ru 45 Rh 46 47 Pd Ag 48 Cd 49 50 In Sn 51 Sb Te I 83.798(2) 54 Xe ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 101.07(2) 102.91 106.42 107.87 112.41 114.82 118.71 121.76 127.60(3) 126.90 131.29 76 77 78 79 80 81 82 83 84 85 Os Ir Pt Au gold mercury thallium lead bismuth 196.97 200.59 [204.38, 204.39] 207.2 208.98 113 114 nihonium flerovium hafnium tantalum tungsten rhenium osmium iridium platinum 178.49(2) 180.95 183.84 186.21 190.23(3) 192.22 195.08 Hg Tl Pb Bi Po polonium At astatine 86 Rn radon 204.38 87 Fr francium 88 Ra radium 89-103 actinoids 104 Rf rutherfordium 57 La 105 Db dubnium 58 Ce 106 Sg seaborgium 59 Pr 107 Bh bohrium 60 Nd lanthanum cerium praseodymium neodymium 138.91 140.12 140.91 144.24 89 90 91 92 Ac actinium Th Pa U thorium protactinium uranium 232.04 231.04 238.03 108 Hs hassium 61 Pm promethium 93 Np neptunium 109 Mt meitnerium 62 Sm 110 Ds darmstadtium 63 Eu 111 Rg roentgenium 64 Gd 112 Cn copernicium 65 Tb Nh 66 Dy Fl 67 Ho 115 Mc moscovium 68 Er 116 Lv livermorium 69 Tm 117 Ts tennessine 70 Yb 118 Og oganesson 71 Lu samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium 150.36(2) 151.96 157.25(3) 158.93 162.50 164.93 167.26 168.93 173.05 174.97 94 95 96 97 98 99 100 101 102 Pu plutonium Am americium Cm curium For notes and updates to this table, see www.iupac.org. This version is dated 1 December 2018. Copyright © 2018 IUPAC, the International Union of Pure and Applied Chemistry. Bk berkelium Cf californium Es einsteinium Fm fermium Md mendelevium No nobelium 103 Lr lawrencium