Fossils Table of Geologic Time A List of the Elements, the Abbreviations Used for Them, and Their Atomic Weight, Which Is Approximately the Number of Times Heavier They Are Than Hydrogen. Name Oxygen = 16 Aluminium, Al 27 Antimony, Sb 122 Argon, Ar 40 Arsenic, As 75 Barium, Ba 137 Beryllium, Be 9 Bismuth, Bi 209 Boron, B 11 Bromine, Br 80 Cadmium, Cd 112 Cæsium, Cs 132 Calcium, Ca 40 Carbon, C 12 Cerium, Ce 140 Chlorine, Cl 35 Chromium, Cr 52 Cobalt, Co 59 Columbium, Cb 93 Copper, Cu 64 Dysprosium, Dy 162 Erbium, Er 167 Europium, Eu 152 Fluorine, F 19 Gadolinium, Gd 157 Gallium, Ga 70 Germanium, Ge 63 Glucinum, Gl 9 Gold, Au 197 Hafnium, Hf 179 Helium, He 4 Holmium, Ho 165 Hydrogen, H 1 Indium, In 115 Iodine, I 127 Iridium, Ir 193 Iron, Fe 56 Krypton, Kr 84 Lanthanum, La 139 Lead, Pb 207 Lithium, Li 7 Lutecium, Lu 175 Magnesium, Mg 24 Manganese, Mn 55 Mercury, Hg 201 Molybdenum, Mo 96 Neodymium, Nd 144 Neon, Ne 20 Nickel, Ni 59 Nitrogen, N 14 Osmium, Os 190 Oxygen, O 16 Palladium, Pd 107 Phosphorus, P 31 Platinum, Pt 195 Potassium, K 39 Præseodymium, Pr 141 Protoactinium, Pa 231 Radium, Ra 226 Radon, Rn 222 Rhenium, Re 186 Rhodium, Rh 103 Rubidium, Rb 85 Ruthenium, Ru 102 Samarium, Sm 150 Scandium, Sc 45 Selenium, Se 79 Silicon, Si 28 Silver, Ag 108 Sodium, Na 23 Strontium, Sr 88 Sulphur, S 32 Tantalum, Ta 181 Tellurium, Te 128 Terbium, Tb 159 Thallium, Tl 204 Thorium, Th 232 Thulium, Tu 169 Tin, Sn 119 Titanium, Ti 48 Tungsten, W 184 Uranium, U 238 Vanadium, V 51 Xenon, Xe 131 Ytterbium, Yt 173 Yttrium, Y 89 Zinc, Zn 65 Zirconium, Zr 91