Periodic Table of Elements List
| # | Symbol | Name | Standard atomic weight (NIST) |
|---|---|---|---|
| 1 | H | Hydrogen | [1.00784,1.00811] |
| 2 | He | Helium | 4.002602(2) |
| 3 | Li | Lithium | [6.938,6.997] |
| 4 | Be | Beryllium | 9.0121831(5) |
| 5 | B | Boron | [10.806,10.821] |
| 6 | C | Carbon | [12.0096,12.0116] |
| 7 | N | Nitrogen | [14.00643,14.00728] |
| 8 | O | Oxygen | [15.99903,15.99977] |
| 9 | F | Fluorine | 18.998403163(6) |
| 10 | Ne | Neon | 20.1797(6) |
| 11 | Na | Sodium | 22.98976928(2) |
| 12 | Mg | Magnesium | [24.304,24.307] |
| 13 | Al | Aluminium | 26.9815385(7) |
| 14 | Si | Silicon | [28.084,28.086] |
| 15 | P | Phosphorus | 30.973761998(5) |
| 16 | S | Sulfur | [32.059,32.076] |
| 17 | Cl | Chlorine | [35.446,35.457] |
| 18 | Ar | Argon | 39.948(1) |
| 19 | K | Potassium | 39.0983(1) |
| 20 | Ca | Calcium | 40.078(4) |
| 21 | Sc | Scandium | 44.955908(5) |
| 22 | Ti | Titanium | 47.867(1) |
| 23 | V | Vanadium | 50.9415(1) |
| 24 | Cr | Chromium | 51.9961(6) |
| 25 | Mn | Manganese | 54.938044(3) |
| 26 | Fe | Iron | 55.845(2) |
| 27 | Co | Cobalt | 58.933194(4) |
| 28 | Ni | Nickel | 58.6934(4) |
| 29 | Cu | Copper | 63.546(3) |
| 30 | Zn | Zinc | 65.38(2) |
| 31 | Ga | Gallium | 69.723(1) |
| 32 | Ge | Germanium | 72.630(8) |
| 33 | As | Arsenic | 74.921595(6) |
| 34 | Se | Selenium | 78.971(8) |
| 35 | Br | Bromine | [79.901,79.907] |
| 36 | Kr | Krypton | 83.798(2) |
| 37 | Rb | Rubidium | 85.4678(3) |
| 38 | Sr | Strontium | 87.62(1) |
| 39 | Y | Yttrium | 88.90584(2) |
| 40 | Zr | Zirconium | 91.224(2) |
| 41 | Nb | Niobium | 92.90637(2) |
| 42 | Mo | Molybdenum | 95.95(1) |
| 43 | Tc | Technetium | [98] |
| 44 | Ru | Ruthenium | 101.07(2) |
| 45 | Rh | Rhodium | 102.90550(2) |
| 46 | Pd | Palladium | 106.42(1) |
| 47 | Ag | Silver | 107.8682(2) |
| 48 | Cd | Cadmium | 112.414(4) |
| 49 | In | Indium | 114.818(1) |
| 50 | Sn | Tin | 118.710(7) |
| 51 | Sb | Antimony | 121.760(1) |
| 52 | Te | Tellurium | 127.60(3) |
| 53 | I | Iodine | 126.90447(3) |
| 54 | Xe | Xenon | 131.293(6) |
| 55 | Cs | Caesium | 132.90545196(6) |
| 56 | Ba | Barium | 137.327(7) |
| 57 | La | Lanthanum | 138.90547(7) |
| 58 | Ce | Cerium | 140.116(1) |
| 59 | Pr | Praseodymium | 140.90766(2) |
| 60 | Nd | Neodymium | 144.242(3) |
| 61 | Pm | Promethium | [145] |
| 62 | Sm | Samarium | 150.36(2) |
| 63 | Eu | Europium | 151.964(1) |
| 64 | Gd | Gadolinium | 157.25(3) |
| 65 | Tb | Terbium | 158.92535(2) |
| 66 | Dy | Dysprosium | 162.500(1) |
| 67 | Ho | Holmium | 164.93033(2) |
| 68 | Er | Erbium | 167.259(3) |
| 69 | Tm | Thulium | 168.93422(2) |
| 70 | Yb | Ytterbium | 173.054(5) |
| 71 | Lu | Lutetium | 174.9668(1) |
| 72 | Hf | Hafnium | 178.49(2) |
| 73 | Ta | Tantalum | 180.94788(2) |
| 74 | W | Tungsten | 183.84(1) |
| 75 | Re | Rhenium | 186.207(1) |
| 76 | Os | Osmium | 190.23(3) |
| 77 | Ir | Iridium | 192.217(3) |
| 78 | Pt | Platinum | 195.084(9) |
| 79 | Au | Gold | 196.966569(5) |
| 80 | Hg | Mercury | 200.592(3) |
| 81 | Tl | Thallium | [204.382,204.385] |
| 82 | Pb | Lead | 207.2(1) |
| 83 | Bi | Bismuth | 208.98040(1) |
| 84 | Po | Polonium | [209] |
| 85 | At | Astatine | [210] |
| 86 | Rn | Radon | [222] |
| 87 | Fr | Francium | [223] |
| 88 | Ra | Radium | [226] |
| 89 | Ac | Actinium | [227] |
| 90 | Th | Thorium | 232.0377(4) |
| 91 | Pa | Protactinium | 231.03588(2) |
| 92 | U | Uranium | 238.02891(3) |
| 93 | Np | Neptunium | [237] |
| 94 | Pu | Plutonium | [244] |
| 95 | Am | Americium | — |
| 96 | Cm | Curium | — |
| 97 | Bk | Berkelium | — |
| 98 | Cf | Californium | — |
| 99 | Es | Einsteinium | — |
| 100 | Fm | Fermium | — |
| 101 | Md | Mendelevium | — |
| 102 | No | Nobelium | — |
| 103 | Lr | Lawrencium | — |
| 104 | Rf | Rutherfordium | — |
| 105 | Db | Dubnium | — |
| 106 | Sg | Seaborgium | — |
| 107 | Bh | Bohrium | — |
| 108 | Hs | Hassium | — |
| 109 | Mt | Meitnerium | — |
| 110 | Ds | Darmstadtium | — |
| 111 | Rg | Roentgenium | — |
| 112 | Cn | Copernicium | — |
| 113 | Nh | Nihonium | — |
| 114 | Fl | Flerovium | — |
| 115 | Mc | Moscovium | — |
| 116 | Lv | Livermorium | — |
| 117 | Ts | Tennessine | — |
| 118 | Og | Oganesson | — |
The periodic table as a working list rather than a poster: all 118 elements with their number, symbol, name and the standard atomic weight NIST publishes - filter to find an element by symbol, name, number, or category, and click any row to copy its symbol.
The weights are verbatim from NIST’s atomic weights table, including its honest notation: bracketed intervals for elements whose natural isotopic mix varies, and uncertainties in the final digits.
How to use
- Type a symbol (Fe), a name (iron), a number (26) or a category (gas) - the table narrows live.
- Click any row to copy the element symbol for a lab note or a formula.
- Read the weights column with NIST notation in mind: [1.00784, 1.00811] is an interval across natural samples, 4.002602(2) means ±0.000002 on the last digit.
Frequently asked questions
Why do some weights have brackets or parentheses?
NIST notation: bracketed intervals like [1.00784, 1.00811] mark elements - hydrogen among them - whose isotopic composition differs between natural sources, so no single number is honest. Parentheses give the uncertainty: 4.002602(2) is 4.002602 ± 0.000002.
Why do elements 95 to 118 show a dash instead of a weight?
They have no stable isotope at all - americium and everything after is synthetic, so no natural isotopic mix exists to average. NIST’s table lists no standard atomic weight for them; the dash says exactly that instead of inventing a number.
What is the difference between atomic weight and mass number?
Mass number is a count - protons plus neutrons in one isotope, always a whole number. Atomic weight is the weighted average across isotopes, which is why chlorine is 35.45 rather than 35 or 36.
Which element has the heaviest standard atomic weight?
Among naturally occurring elements, uranium at 238.02891(3) - element 92. Everything beyond bismuth (83) is radioactive, and everything beyond uranium does not occur naturally in meaningful amounts.