Interactive periodic table of ionic radius in picometers. ElementWorks is a free interactive periodic table: hover an element to preview it, click it for its full card, or pick another view from the Show menu.
Ionic radius describes the size of an ion in picometers (pm), here for the common simple ion of each element. Cations are smaller than the atoms they come from because losing electrons reduces repulsion and often empties an outer shell. Anions are larger than their atoms because added electrons increase repulsion. Among isoelectronic ions, more protons mean a smaller ion.
| No. | Symbol | Element | Ion size (pm) |
|---|---|---|---|
| 1 | H | Hydrogen | — |
| 2 | He | Helium | — |
| 3 | Li | Lithium | 76 pm |
| 4 | Be | Beryllium | 45 pm |
| 5 | B | Boron | 27 pm |
| 6 | C | Carbon | — |
| 7 | N | Nitrogen | 146 pm |
| 8 | O | Oxygen | 140 pm |
| 9 | F | Fluorine | 133 pm |
| 10 | Ne | Neon | — |
| 11 | Na | Sodium | 102 pm |
| 12 | Mg | Magnesium | 72 pm |
| 13 | Al | Aluminium | 54 pm |
| 14 | Si | Silicon | — |
| 15 | P | Phosphorus | 212 pm |
| 16 | S | Sulfur | 184 pm |
| 17 | Cl | Chlorine | 181 pm |
| 18 | Ar | Argon | — |
| 19 | K | Potassium | 138 pm |
| 20 | Ca | Calcium | 100 pm |
| 21 | Sc | Scandium | 75 pm |
| 22 | Ti | Titanium | 61 pm |
| 23 | V | Vanadium | — |
| 24 | Cr | Chromium | 62 pm |
| 25 | Mn | Manganese | 83 pm |
| 26 | Fe | Iron | 65 pm |
| 27 | Co | Cobalt | 75 pm |
| 28 | Ni | Nickel | 69 pm |
| 29 | Cu | Copper | 73 pm |
| 30 | Zn | Zinc | 74 pm |
| 31 | Ga | Gallium | 62 pm |
| 32 | Ge | Germanium | — |
| 33 | As | Arsenic | — |
| 34 | Se | Selenium | 198 pm |
| 35 | Br | Bromine | 196 pm |
| 36 | Kr | Krypton | — |
| 37 | Rb | Rubidium | 152 pm |
| 38 | Sr | Strontium | 118 pm |
| 39 | Y | Yttrium | 90 pm |
| 40 | Zr | Zirconium | 72 pm |
| 41 | Nb | Niobium | — |
| 42 | Mo | Molybdenum | — |
| 43 | Tc | Technetium | — |
| 44 | Ru | Ruthenium | — |
| 45 | Rh | Rhodium | — |
| 46 | Pd | Palladium | — |
| 47 | Ag | Silver | 115 pm |
| 48 | Cd | Cadmium | 95 pm |
| 49 | In | Indium | 80 pm |
| 50 | Sn | Tin | 118 pm |
| 51 | Sb | Antimony | — |
| 52 | Te | Tellurium | 221 pm |
| 53 | I | Iodine | 220 pm |
| 54 | Xe | Xenon | — |
| 55 | Cs | Cesium | 167 pm |
| 56 | Ba | Barium | 135 pm |
| 57 | La | Lanthanum | 103 pm |
| 58 | Ce | Cerium | — |
| 59 | Pr | Praseodymium | — |
| 60 | Nd | Neodymium | — |
| 61 | Pm | Promethium | — |
| 62 | Sm | Samarium | — |
| 63 | Eu | Europium | — |
| 64 | Gd | Gadolinium | — |
| 65 | Tb | Terbium | — |
| 66 | Dy | Dysprosium | — |
| 67 | Ho | Holmium | — |
| 68 | Er | Erbium | — |
| 69 | Tm | Thulium | — |
| 70 | Yb | Ytterbium | — |
| 71 | Lu | Lutetium | — |
| 72 | Hf | Hafnium | — |
| 73 | Ta | Tantalum | — |
| 74 | W | Tungsten | — |
| 75 | Re | Rhenium | — |
| 76 | Os | Osmium | — |
| 77 | Ir | Iridium | — |
| 78 | Pt | Platinum | — |
| 79 | Au | Gold | 137 pm |
| 80 | Hg | Mercury | 102 pm |
| 81 | Tl | Thallium | 150 pm |
| 82 | Pb | Lead | 119 pm |
| 83 | Bi | Bismuth | 103 pm |
| 84 | Po | Polonium | — |
| 85 | At | Astatine | — |
| 86 | Rn | Radon | — |
| 87 | Fr | Francium | — |
| 88 | Ra | Radium | — |
| 89 | Ac | Actinium | — |
| 90 | Th | Thorium | — |
| 91 | Pa | Protactinium | — |
| 92 | U | Uranium | — |
| 93 | Np | Neptunium | — |
| 94 | Pu | Plutonium | — |
| 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 atom loses its outer electrons, often the whole outer shell, and the remaining electrons are pulled in more strongly by the same nuclear charge.
Extra electrons repel each other more while the nuclear charge stays the same, so the electron cloud expands.
Species with the same number of electrons, such as O²⁻, F⁻, Na⁺ and Mg²⁺. As the proton count rises, the radius shrinks.
© 2026 Prof. Rami El Oweini. All rights reserved.