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Astronomy

K | The Chemical Elements

AstronomyK | The Chemical Elements
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The Chemical Elements
Element Symbol Atomic Number Atomic Weight1 Percentage of Naturally Occurring Elements in the Universe
Hydrogen H 1 1.008 75
Helium He 2 4.003 23
Lithium Li 3 6.94 6 × 10−7
Beryllium Be 4 9.012 1 × 10−7
Boron B 5 10.821 1 × 10−7
Carbon C 6 12.011 0.5
Nitrogen N 7 14.007 0.1
Oxygen O 8 15.999 1
Fluorine F 9 18.998 4 × 10−5
Neon Ne 10 20.180 0.13
Sodium Na 11 22.990 0.002
Magnesium Mg 12 24.305 0.06
Aluminum Al 13 26.982 0.005
Silicon Si 14 28.085 0.07
Phosphorus P 15 30.974 7 × 10−4
Sulfur S 16 32.06 0.05
Chlorine Cl 17 35.45 1 × 10−4
Argon Ar 18 39.948 0.02
Potassium K 19 39.098 3 × 10−4
Calcium Ca 20 40.078 0.007
Scandium Sc 21 44.956 3 × 10−6
Titanium Ti 22 47.867 3 × 10−4
Vanadium V 23 50.942 3 × 10−4
Chromium Cr 24 51.996 0.0015
Manganese Mn 25 54.938 8 × 10−4
Iron Fe 26 55.845 0.11
Cobalt Co 27 58.933 3 × 10−4
Nickel Ni 28 58.693 0.006
Copper Cu 29 63.546 6 × 10−6
Zinc Zn 30 65.38 3 × 10−5
Gallium Ga 31 69.723 1 × 10−6
Germanium Ge 32 72.630 2 × 10−5
Arsenic As 33 74.922 8 × 10−7
Selenium Se 34 78.971 3 × 10−6
Bromine Br 35 79.904 7 × 10−7
Krypton Kr 36 83.798 4 × 10−6
Rubidium Rb 37 85.468 1 × 10−6
’Strontium Sr 38 87.62 4 × 10−6
Yttrium Y 39 88.906 7 × 10−7
Zirconium Zr 40 91.224 5 × 10−6
Niobium Nb 41 92.906 2 × 10−7
Molybdenum Mo 42 95.95 5 × 10−7
Technetium Tc 43 (98) —
Ruthenium Ru 44 101.07 4 × 10−7
Rhodium Rh 45 102.906 6 × 10−8
Palladium Pd 46 106.42 2 × 10−7
Silver Ag 47 107.868 6 × 10−8
Cadmium Cd 48 112.414 2 × 10−7
Indium In 49 114.818 3 × 10−8
Tin Sn 50 118.710 4 × 10−7
Antimony Sb 51 121.760 4 × 10−8
Tellurium Te 52 127.60 9 × 10−7
Iodine I 53 126.904 1 × 10−7
Xenon Xe 54 131.293 1 × 10−6
Cesium Cs 55 132.905 8 × 10−8
Barium Ba 56 137.327 1 × 10−6
Lanthanum La 57 138.905 2 × 10−7
Cerium Ce 58 140.116 1 × 10−6
Praseodymium Pr 59 140.907 2 × 10−7
Neodymium Nd 60 144.242 1 × 10−6
Promethium Pm 61 (145) —
Samarium Sm 62 150.36 5 × 10−7
Europium Eu 63 151.964 5 × 10−8
Gadolinium Gd 64 157.25 2 × 10−7
Terbium Tb 65 158.925 5 × 10−8
Dysprosium Dy 66 162.500 2 × 10−7
Holmium Ho 67 164.930 5 × 10−8
Erbium Er 68 167.259 2 × 10−7
Thulium Tm 69 168.934 1 × 10−8
Ytterbium Yb 70 173.054 2 × 10−7
Lutetium Lu 71 174.967 1 × 10−8
Hafnium Hf 72 178.49 7 × 10−8
Tantalum Ta 73 180.948 8 × 10−9
Tungsten W 74 183.84 5 × 10−8
Rhenium Re 75 186.207 2 × 10−8
Osmium Os 76 190.23 3 × 10−7
Iridium Ir 77 192.217 2 × 10−7
Platinum Pt 78 195.084 5 × 10−7
Gold Au 79 196.967 6 × 10−8
Mercury Hg 80 200.592 1 × 10−7
Thallium TI 81 204.38 5 × 10−8
Lead Pb 82 207.2 1 × 10−6
Bismuth Bi 83 208.980 7 × 10−8
Polonium Po 84 (209) —
Astatine At 85 (210) —
Radon Rn 86 (222) —
Francium Fr 87 (223) —
Radium Ra 88 (226) —
Actinium Ac 89 (227) —
Thorium Th 90 232.038 4 × 10−8
Protactinium Pa 91 231.036 —
Uranium U 92 238.029 2 × 10−8
Neptunium Np 93 (237) —
Plutonium Pu 94 (244) —
Americium Am 95 (243) —
Curium Cm 96 (247) —
Berkelium Bk 97 (247) —
Californium Cf 98 (251) —
Einsteinium Es 99 (252) —
Fermium Fm 100 (257) —
Mendelevium Md 101 (258) —
Nobelium No 102 (259) —
Lawrencium Lr 103 (262) —
Rutherfordium Rf 104 (267) —
Dubnium Db 105 (268) —
Seaborgium Sg 106 (271) —
Bohrium Bh 107 (272) —
Hassium Hs 108 (270) —
Meitnerium Mt 109 (276) —
Darmstadtium Ds 110 (281) —
Roentgenium Rg 111 (280) —
Copernicium Cn 112 (285) —
Nihonium Nh 113 (284) —
Flerovium Fl 114 (289) —
Moskovium Mc 115 (288) —
Livermorium Lv 116 (293) —
Tennessine Ts 117 (294) —
Oganesson Og 118 (294) —
Table K1

Footnotes

  • 1Where mean atomic weights have not been well determined, the atomic mass numbers of the most stable isotopes are given in parentheses.
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