IUPAC Atomic Weights of the Elements List

IUPAC Atomic Weights of the Elements List This is the 2013 list of atomic weights of the elements in increasing atomic number, as accepted by the IUPAC. The table is based on the Standard Atomic Weights Revised v2 (Sept 24,2013). The list includes the 2013  changes to the atomic weights of 19 elements: arsenic, beryllium, cadmium, cesium, cobalt, fluorine, gold, holmium, manganese, molybdenum, niobium, phosphorus, praseodymium, scandium,  selenium, thorium, thulium and yttrium. These values remain current until the IUPAC sees the need to revise them. Values given by the [a;b] notation highlights the range of atomic weights for the element. For these elements, the atomic weight is dependent on the physical and chemical history of the element. The interval reflects the minimum (a) and the maximum (b) values for the element.Values given in chevron brackets (e.g., Fm 257) are the mass numbers of the longest-lived isotope of elements that do not have stable nuclides. However, atomic weights are provided for Th, Pa, and U because these elements have a characteristic abundance in the earths crust. For detailed element facts, consult the  Periodic Table  for individual elements. Atomic Number - Symbol - Name - Atomic Weight 1   H   - Hydrogen - [1.007 84; 1.008 11]2   He - Helium - 4.002 602(2)3   Li - Lithium - [6.938; 6.997]4   Be - Beryllium - 9.012 1831(5)5   B   - Boron - [10.806; 10.821]6   C   - Carbon - [12.0096; 12.0116]7   N   - Nitrogen - [14.006 43; 14.007 28]8   O   - Oxygen - [15.999 03; 15.999 77]9   F   - Fluorine - 18.998 403 163(6)10 Ne - Neon - 20.1797(6)11 Na - Sodium - 22.989 769 28(2)12 Mg - Magnesium - [24.304, 24.307]13 Al - Aluminium - 26.981 5385(7)14 Si - Silicon - [28.084; 28.086]15 P   - Phosphorus - 30.973 761 998(5)16 S   - Sulfur - [32.059; 32.076]17 Cl - Chlorine - [35.446; 35.457]18 Ar - Argon - 39.948(1)19 K   - Potassium - 39.0983(1)20 Ca - Calcium - 40.078(4)21 Sc - Scandium - 44.955 908(5)22 Ti - Titanium - 47.867(1)23 V   - Vanadium - 50.9415(1)24 Cr - Chromium - 51.9961(6)25 Mn - Manganese - 54.938 044(3)26 Fe - Iron - 55.845(2)27 Co - Cobalt - 58.933 194(4)28 Ni - Nickel 58.6934(4)29 Cu - Copper - 63.546(3)30 Zn - Zinc - 65.3 8(2)31 Ga - Gallium - 69.723(1)32 Ge - Germanium - 72.630(8)33 As - Arsenic - 74.921 595(6)34 Se - Selenium - 78.971(8)35 Br - Bromine - [79.901, 79.907]36 Kr - Krypton - 83.798(2)37 Rb - Rubidium - 85.4678(3)38 Sr - Strontium - 87.62(1)39 Y   - Yttrium - 88.905 84(2)40 Zr - Zirconium - 91.224(2)41 Nb - Niobium - 92.906 37(2)42 Mo - Molybdenum - 95.95(1)43 Tc - Technetium - 9844 Ru - Ruthenium - 101.07(2)45 Rh - Rhodium - 102.905 50(2)46 Pd - Palladium - 106.42(1)47 Ag - Silver - 107.8682(2)48 Cd - Cadmium - 112.414(4)49 In - Indium - 114.818(1)50 Sn - Tin - 118.710(7)51 Sb - Antimony - 121.760(1)52 Te - Tellurium - 127.60(3)53 I   - Iodine - 126.904 47(3)54 Xe - Xenon - 131.293(6)55 Cs - Cesium - 132.905 451 96(6)56 Ba - Barium - 137.327(7)57 La - Lanthanum - 138.905 47(7)58 Ce - Cerium - 140.116(1)59 Pr - Praseodymium - 140.907 66(2)60 Nd - Neodymium - 144.242(3)61 Pm - Promethium - 14562 Sm - Samarium - 150.36(2)63 Eu - Europium - 151.964(1)64 Gd - Gadolinium - 157.25(3)65 Tb - Terbium - 158.925 35(2)66 Dy - Dysprosium - 162.500(1)67 Ho - Holmium - 164.930 33(2)68 Er - Erbium - 167.259(3)69 Tm - Thulium - 168.934 22(2)70 Yb - Ytterbium - 173.054(5)71 Lu - Lutetium - 174.9668(1)72 Hf - Hafnium - 178.49(2)73 Ta - Tantalum - 180.947 88(2)74 W - Tungsten - 183.84(1)75 Re - Rhenium - 186.207(1)76 Os - Osmium - 190.23(3)77 Ir - Iridium - 192.217(3)78 Pt - Platinum - 195.084(9)79 Au - Gold - 196.966 569(5)80 Hg - Mercury - 200.592(3)81 Tl - Thallium - [204.382; 204.385]82 Pb - Lead - 207.2(1)83 Bi - Bismuth - 208.980 40(1)84 Po - Polonium - 20985 At - Astatine - 21086 Rn - Radon - 22287 Fr - Francium - 22388 Ra - Radium - 22689 Ac - Actinium - 22790 Th - Thorium - 232.037 7(4)91 Pa - Protactinium - 231.035 88(2)92 U   - Uranium - 238.028 91(3)93 Np - Neptunium - 23794 Pu - Plutonium - 24495 Am - Americium - 24396 Cm - Curium - 24797 Bk - Berkelium - 24798 Cf - Californium - 25199 Es - Einsteinium - 252100 Fm - Fermium - 257101 Md - Mendelevium - 258102 No - Nobelium - 259103 Lr - Lawrencium - 262104 Rf - Rutherfordium - 267105 Db - Dubnium - 268106 Sg - Seaborgium - 271107 Bh - Bohrium - 272108 Hs - Hassium - 270109 Mt - Meitnerium - 276110 Ds - Darmstadtium - 281111 Rg - Roentgenium - 280112 Cn - Copernicium - 285113 Uut - Ununtrium - 284114 Fl - Flerovium - 289115 Uup - Ununpentium - 288116 Lv - Livermorium - 293118 Uuo - Ununoctium - 294