This is a list of chemical elements and their atomic properties, ordered by atomic number (Z).
Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
Table ZNameSymbolAverageatomic massElectronegativity(Pauling)First Ionization Energy (eV)Radii (pm)ValenceelectronsAtomicVan der WaalsCovalent 1Hydrogen H 1.0082.213.5984425120381 2Helium He 4.002602(2) — 24.5874131140322 3Lithium Li 6.941(2)0.985.391721451821341 4Beryllium Be 9.012182(3)1.579.3227105 — 902 5Boron B 10.811(7)2.048.2980385 — 823 6Carbon C 12.0107(8)2.5511.260370170774 7Nitrogen N 14.0067(2)3.0414.5341465155755 8Oxygen O 15.9994(3)3.4413.6180660152736 9Fluorine F 18.9984032(5)3.9817.4228250147717 10Neon Ne 20.1797(6) — 21.564638154698 11Sodium Na 22.98976928(2) 0.935.139081802271541 12Magnesium Mg 24.3050(6) 1.317.646241501731302 13Aluminium Al 26.9815386(8) 1.61 5.98577125 — 1183 14Silicon Si 28.0855(3)1.9 8.15169 1102101114 15Phosphorus P 30.973762(2) 2.1910.486691001801065 16Sulfur S 32.065(5)2.5810.360011001801026 17Chlorine Cl 35.453(2)3.1612.96764100175997 18Argon Ar 39.948(1) — 15.7596271188978 19Potassium K 39.0983(1)0.824.340662202751961 20Calcium Ca 40.078(4)16.11316180 — 1742 21Scandium Sc 44.955912(6)1.366.5615160 — 1442 22Titanium Ti 47.867(1)1.546.8281140 — 1362 23Vanadium V 50.9415(1)1.636.7462135 — 1252 24Chromium Cr 51.9961(6)1.666.7665140 — 1271 25Manganese Mn 54.938045(5)1.557.43402140 — 1392 26Iron Fe 55.845(2)1.837.9024140 — 1252 27Cobalt Co 58.933195(5)1.917.63981351631212 28Nickel Ni 58.6934(4)1.887.881135 — 1262 29Copper Cu 63.546(3)1.97.726381351401381 30Zinc Zn 65.38(2)1.659.39421351391312 31Gallium Ga 69.723(1)1.815.99931301871263 32Germanium Ge 72.63(1)2.017.8994125 — 1224 33Arsenic As 74.92160(2)2.189.78861151851195 34Selenium Se 78.96(3)2.559.752381151901166 35Bromine Br 79.904(1)2.9611.813811151851147 36Krypton Kr 83.798(2)313.99961882021108 37Rubidium Rb 85.4678(3)0.824.17713235 — 2111 38Strontium Sr 87.62(1)0.955.6949200 — 1922 39Yttrium Y 88.90585(2)1.226.2171180 — 1622 40Zirconium Zr 91.224(2)1.336.6339155 — 1482 41Niobium Nb 92.90638(2)1.66.75885145 — 1371 42Molybdenum Mo 95.96(2)2.167.09243145 — 1451 43Technetium Tc 1.97.28135 — 1561 44Ruthenium Ru 101.07(2)2.27.3605130 — 1261 45Rhodium Rh 102.90550(2)2.287.4589135 — 1351 46Palladium Pd 106.42(1)2.28.3369140163131 47Silver Ag 107.8682(2)1.937.57621601721531 48Cadmium Cd 112.411(8)1.698.99381551581482 49Indium In 114.818(3)1.785.786361551931443 50Tin Sn 118.710(7)1.967.34391452171414 51Antimony Sb 121.760(1)2.058.6084145 — 1385 52Tellurium Te 127.60(3)2.19.00961402061356 53Iodine I 126.90447(3)2.6610.451261401981337 54Xenon Xe 131.293(6)2.612.12981082161308 55Caesium Cs 132.9054519(2)0.793.8939260 — 2251 56Barium Ba 137.327(7)0.895.2117215 — 1982 57Lanthanum La 138.90547(7)1.15.5769195 — 1692 58Cerium Ce 140.116(1)1.125.5387185 — — 2 59Praseodymium Pr 140.90765(2)1.135.473185 — — 2 60Neodymium Nd 144.242(3)1.145.525185 — — 2 61Promethium Pm — 5.582185 — — 2 62Samarium Sm 150.36(2)1.175.6436185 — — 2 63Europium Eu 151.964(1) — 5.6704185 — — 2 64Gadolinium Gd 157.25(3)1.26.1501180 — — 2 65Terbium Tb 158.92535(2) — 5.8638175 — — 2 66Dysprosium Dy 162.500(1)1.225.9389175 — — 2 67Holmium Ho 164.93032(2)1.236.0215175 — — 2 68Erbium Er 167.259(3)1.246.1077175 — — 2 69Thulium Tm 168.93421(2)1.256.18431175 — — 2 70Ytterbium Yb 173.054(5) — 6.25416175 — — 2 71Lutetium Lu 174.9668(1)1.275.4259175 — 160 2 72Hafnium Hf 178.49(2)1.36.82507155 — 150 2 73Tantalum Ta 180.94788(2)1.57.5496145 — 1382 74Tungsten W 183.84(1)2.367.864135 — 1462 75Rhenium Re 186.207(1)1.97.8335135 — 159 2 76Osmium Os 190.23(3)2.28.4382130 — 1282 77Iridium Ir 192.217(3)2.28.967135 — 1372 78Platinum Pt 195.084(9)2.288.95871351751281 79Gold Au 196.966569(4)2.549.22551351661441 80Mercury Hg 200.59(2)210.43751501551492 81Thallium Tl 204.3833(2) 1.626.1082190196148 3 82Lead Pb 207.2(1)2.337.416661802021474 83Bismuth Bi 208.98040(1)2.027.2856160 — 1465 84Polonium Po 28.417190 — — 6 85Astatine At 2.2 — — — 7 86Radon Rn — 10.7485120 — 1458 87Francium Fr 0.74.0727 — — — 1 88Radium Ra 0.95.2784215 — — 2 89Actinium Ac 1.15.17195 — — 2 90Thorium Th 232.03806(2)1.36.3067180 — — 2 91Protactinium Pa 231.03588(2)1.55.89180 — — 2 92Uranium U 238.02891(3)1.386.19405175186 — 2 93Neptunium Np 1.366.2657175 — — 2 94Plutonium Pu 1.286.0262175 — — 2 95Americium Am 1.35.9738175 — — 2 96Curium Cm 1.35.9915 2 97Berkelium Bk 1.36.1979 2 98Californium Cf 1.36.2817 2 99Einsteinium Es 1.36.42 2 100Fermium Fm 1.36.5 2 101Mendelevium Md 1.36.58 2 102Nobelium No 1.36.65 2 103Lawrencium Lr 1.34.9 3 104Rutherfordium Rf 6 2 105Dubnium Db 2 106Seaborgium Sg 2 107Bohrium Bh 2 108Hassium Hs 2 109Meitnerium Mt 110Darmstadtium Ds 111Roentgenium Rg 112Copernicium Cn 113Nihonium Nh 114Flerovium Fl 115Moscovium Mc 116Livermorium Lv 117Tennessine Ts 118Oganesson Og
[*] a few atomic radii are calculated, not experimental [—] a long dash marks properties for which there is no data available [ ] a blank marks properties for which no data has been found
References