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Relative Atomic Mass
| The relative atomic mass is the mass of an atom relative to the twelfth part of the mass of the most abundant isotope of carbon (C-12). The relative atomic mass is a dimensionless number. Hydrogen has the smallest atomic mass (1.00794). | In general the atomic mass increases with the atomic number, with few exceptions. For instance Tellurium (Z = 52) has a larger relative atomic mass than Iodine (Z = 53). |
| Z | Name | Relative atomic mass |
| 1 | Hydrogen | 1.00794 |
| 2 | Helium | 4.002602 |
| 3 | Lithium | 6.941 |
| 4 | Beryllium | 9.012182 |
| 5 | Boron | 10.811 |
| 6 | Carbon | 12.011 |
| 7 | Nitrogen | 14.00674 |
| 8 | Oxygen | 15.9994 |
| 9 | Fluorine | 18.9984032 |
| 10 | Neon | 20.1797 |
| 11 | Sodium | 22.989768 |
| 12 | Magnesium | 24.3050 |
| 13 | Aluminium | 26.981539 |
| 14 | Silicon | 28.0855 |
| 15 | Phosphorus | 30.973762 |
| 16 | Sulfur | 32.066 |
| 17 | Chlorine | 35.4527 |
| 18 | Argon | 39.948 |
| 19 | Potassium | 39.0983 |
| 20 | Calcium | 40.078 |
| 21 | Scandium | 44.955910 |
| 22 | Titanium | 47.88 |
| 23 | Vanadium | 50.9415 |
| 24 | Chromium | 51.9961 |
| 25 | Manganese | 54.93805 |
| 26 | Iron | 55.847 |
| 27 | Cobalt | 58.9332 |
| 28 | Nickel | 58.69 |
| 29 | Copper | 63.546 |
| 30 | Zinc | 65.39 |
| 31 | Gallium | 69.723 |
| 32 | Germanium | 72.61 |
| 33 | Arsenic | 74.92159 |
| 34 | Selenium | 78.96 |
| 35 | Bromine | 79.904 |
| 36 | Krypton | 83.80 |
| 37 | Rubidium | 85.4678 |
| 38 | Strontium | 87.62 |
| 39 | Yttrium | 88.90585 |
| 40 | Zirconium | 91.224 |
| 41 | Niobium | 92.90638 |
| 42 | Molybdenum | 95.94 |
| 43 | Technetium | 98.9063 |
| 44 | Ruthenium | 101.07 |
| 45 | Rhodium | 102.90550 |
| 46 | Palladium | 106.42 |
| 47 | Silver | 107.8682 |
| 48 | Cadmium | 112.411 |
| 49 | Indium | 114.82 |
| 50 | Tin | 118.710 |
| 51 | Antimony | 121.75 |
| 52 | Tellurium | 127.60 |
| 53 | Iodine | 126.90447 |
| 54 | Xenon | 131.29 |
| 55 | Caesium | 132.90543 |
| 56 | Barium | 137.327 |
| 57 | Lanthanum | 138.9055 |
| 58 | Cerium | 140.115 |
| 59 | Praseodymium | 140.90765 |
| 60 | Neodymium | 144.24 |
| 61 | Promethium | 146.9151 |
| 62 | Samarium | 150.36 |
| 63 | Europium | 151.965 |
| 64 | Gadolinium | 157.25 |
| 65 | Terbium | 158.92534 |
| 66 | Dysprosium | 162.50 |
| 67 | Holmium | 164.93032 |
| 68 | Erbium | 167.26 |
| 69 | Thulium | 168.93421 |
| 70 | Ytterbium | 173.04 |
| 71 | Lutetium | 174.967 |
| 72 | Hafnium | 178.49 |
| 73 | Tantalum | 180.9479 |
| 74 | Tungsten | 183.85 |
| 75 | Rhenium | 186.207 |
| 76 | Osmium | 190.2 |
| 77 | Iridium | 192.22 |
| 78 | Platinum | 195.08 |
| 79 | Gold | 196.96654 |
| 80 | Mercury | 200.59 |
| 81 | Thallium | 204.3833 |
| 82 | Lead | 207.2 |
| 83 | Bismuth | 208.98037 |
| 84 | Polonium | 208.9824 |
| 85 | Astatine | 209.9871 |
| 86 | Radon | 222.0176 |
| 87 | Francium | 223.0197 |
| 88 | Radium | 226.0254 |
| 89 | Actinium | 227.0278 |
| 90 | Thorium | 232.0381 |
| 91 | Protactinium | 231.0359 |
| 92 | Uranium | 238.0289 |
| 93 | Neptunium | 237.0482 |
| 94 | Plutonium | 244.0642 |
| 95 | Americium | 243.0614 |
| 96 | Curium | 247.0703 |
| 97 | Berkelium | 247.0703 |
| 98 | Californium | 251.0796 |
| 99 | Einsteinium | 252.0829 |
| 100 | Fermium | 257.0951 |
| 101 | Mendelevium | 258.0986 |
| 102 | Nobelium | 259.1009 |
| 103 | Lawrencium | 260.1053 |
| 104 | Rutherfordium | 261.1087 |
| 105 | Dubnium | 262.1138 |
| 106 | Seaborgium | 263.1182 |
| 107 | Bohrium | 262.1229 |
| 108 | Hassium | ca. 265 |
| 109 | Meitnerium | ca. 266 |
| 110 | Unnunnilium | ca. 270 |
| 111 | Unnununium | ca. 272 |
| © B.M.Gammel, last change 18 Feb 1998 |