ABSTRACT
Number Atomic Weight Footnotes Actinium* Ac 89 Aluminum Al 13 26 .9815386(8) Americium* Am 95 Antimony Sb 51 121 .760(1) g Argon Ar 18 39 .948(1) g r Arsenic As 33 74 .92160(2) Astatine* At 85 Barium Ba 56 137 .327(7) Berkelium* Bk 97 Beryllium Be 4 9 .012182(3) Bismuth Bi 83 208 .98040(1) Bohrium* Bh 107 Boron B 5 [10 .806; 10 .821] m Bromine Br 35 79 .904(1) Cadmium Cd 48 112 .411(8) g Calcium Ca 20 40 .078(4) g Californium* Cf 98 Carbon C 6 [12 .0096; 12 .0116] Cerium Ce 58 140 .116(1) g Cesium Cs 55 132 .9054519(2) Chlorine Cl 17 [35 .446; 35 .457] m Chromium Cr 24 51 .9961(6) Cobalt Co 27 58 .933195(5) Copernicium* Cn 112 Copper Cu 29 63 .546(3) r Curium* Cm 96 Darmstadtium* Ds 110 Dubnium* Db 105 Dysprosium Dy 66 162 .500(1) g Einsteinium* Es 99 Erbium Er 68 167 .259(3) g Europium Eu 63 151 .964(1) g Fermium* Fm 100 Fluorine F 9 18 .9984032(5)
Element Symbol Atomic
Number Atomic Weight Footnotes Francium* Fr 87 Gadolinium Gd 64 157 .25(3) g Gallium Ga 31 69 .723(1) Germanium Ge 32 72 .63(1) Gold Au 79 196 .966569(4) Hafnium Hf 72 178 .49(2) Hassium* Hs 108 Helium He 2 4 .002602(2) g r Holmium Ho 67 164 .93032(2) Hydrogen H 1 [1 .00784; 1 .00811] m Indium In 49 114 .818(3) Iodine I 53 126 .90447(3) Iridium Ir 77 192 .217(3) Iron Fe 26 55 .845(2) Krypton Kr 36 83 .798(2) g m Lanthanum La 57 138 .90547(7) g Lawrencium* Lr 103 Lead Pb 82 207 .2(1) g r Lithium Li 3 [6 .938; 6 .997] m Lutetium Lu 71 174 .9668(1) g Magnesium Mg 12 24 .3050(6) Manganese Mn 25 54 .938045(5) Meitnerium* Mt 109 Mendelevium* Md 101 Mercury Hg 80 200 .59(2) Molybdenum Mo 42 95 .96(2) g Neodymium Nd 60 144 .242(3) g Neon Ne 10 20 .1797(6) g m Neptunium* Np 93 Nickel Ni 28 58 .6934(4) r Niobium Nb 41 92 .90638(2) Nitrogen N 7 [14 .00643; 14 .00728] Nobelium* No 102 Osmium Os 76 190 .23(3) g
Element Symbol
Number Atomic Weight Footnotes Oxygen O 8 [15 .99903; 15 .99977] Palladium Pd 46 106 .42(1) g Phosphorus P 15 30 .973762(2) Platinum Pt 78 195 .084(9) Plutonium* Pu 94 Polonium* Po 84 Potassium K 19 39 .0983(1) Praseodymium Pr 59 140 .90765(2) Promethium* Pm 61 Protactinium** Pa 91 231 .03588(2) Radium* Ra 88 Radon* Rn 86 Rhenium Re 75 186 .207(1) Rhodium Rh 45 102 .90550(2) Roentgenium* Rg 111 Rubidium Rb 37 85 .4678(3) g Ruthenium Ru 44 101 .07(2) g Rutherfordium* Rf 104 Samarium Sm 62 150 .36(2) g Scandium Sc 21 44 .955912(6) Seaborgium* Sg 106 Selenium Se 34 78 .96(3) r Silicon Si 14 [28 .084; 28 .086] Silver Ag 47 107 .8682(2) g Sodium Na 11 22 .98976928(2)
Element Symbol
Number Atomic Weight Footnotes Strontium Sr 38 87 .62(1) g r Sulfur S 16 [32 .059; 32 .076] Tantalum Ta 73 180 .94788(2) Technetium* Tc 43 Tellurium Te 52 127 .60(3) g Terbium Tb 65 158 .92535(2) Thallium Tl 81 [204 .382; 204 .385] Thorium** Th 90 232 .03806(2) g Thulium Tm 69 168 .93421(2) Tin Sn 50 118 .710(7) g Titanium Ti 22 47 .867(1) Tungsten W 74 183 .84(1) Ununhexium* Uuh 116 Ununoctium* Uuo 118 Ununpentium* Uup 115 Ununquadium* Uuq 114 Ununtrium* Uut 113 Uranium** U 92 238 .02891(3) g m Vanadium V 23 50 .9415(1) Xenon Xe 54 131 .293(6) g m Ytterbium Yb 70 173 .054(5) g Yttrium Y 39 88 .90585(2) Zinc Zn 30 65 .38(2) r Zirconium Zr 40 91 .224(2) g
TABLE 2. CONVENTIONAL ATOMIC WEIGHTS 2009
Element Symbol Atomic
Number Reference Atomic
Weighta Boron B 5 10 .81 Carbon C 6 12 .011 Chlorine Cl 17 35 .45 Hydrogen H 1 1 .008 Lithium Li 3 6 .94 Nitrogen N 7 14 .007 Oxygen O 8 15 .999 Silicon Si 14 28 .085 Sulfur S 16 32 .06 Thallium Tl 81 204 .38
