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Periodic trend

Atomic Radius

Empirical radius of a neutral atom. Shrinks left to right across a period as nuclear charge pulls electrons in, and jumps at the start of each new period.

Atomic Radius plotted against atomic numberAtomic Radius for 96 of the 118 elements, from 25 to 260 pm. Empirical radius of a neutral atom. Shrinks left to right across a period as nuclear charge pulls electrons in, and jumps at the start of each new period.12345672584143201260 Hydrogen (H): 25 pm Helium (He): 31 pm Lithium (Li): 145 pm Beryllium (Be): 105 pm Boron (B): 85 pm Carbon (C): 70 pm Nitrogen (N): 65 pm Oxygen (O): 60 pm Fluorine (F): 50 pm Neon (Ne): 38 pm Sodium (Na): 180 pm Magnesium (Mg): 150 pm Aluminium (Al): 125 pm Silicon (Si): 110 pm Phosphorus (P): 100 pm Sulfur (S): 100 pm Chlorine (Cl): 100 pm Argon (Ar): 71 pm Potassium (K): 220 pm Calcium (Ca): 180 pm Scandium (Sc): 160 pm Titanium (Ti): 140 pm Vanadium (V): 135 pm Chromium (Cr): 140 pm Manganese (Mn): 140 pm Iron (Fe): 140 pm Cobalt (Co): 135 pm Nickel (Ni): 135 pm Copper (Cu): 135 pm Zinc (Zn): 135 pm Gallium (Ga): 130 pm Germanium (Ge): 125 pm Arsenic (As): 115 pm Selenium (Se): 115 pm Bromine (Br): 115 pm Krypton (Kr): 88 pm Rubidium (Rb): 235 pm Strontium (Sr): 200 pm Yttrium (Y): 180 pm Zirconium (Zr): 155 pm Niobium (Nb): 145 pm Molybdenum (Mo): 145 pm Technetium (Tc): 135 pm Ruthenium (Ru): 130 pm Rhodium (Rh): 135 pm Palladium (Pd): 140 pm Silver (Ag): 160 pm Cadmium (Cd): 155 pm Indium (In): 155 pm Tin (Sn): 145 pm Antimony (Sb): 145 pm Tellurium (Te): 140 pm Iodine (I): 140 pm Xenon (Xe): 108 pm Cesium (Cs): 260 pm Barium (Ba): 215 pm Lanthanum (La): 195 pm Cerium (Ce): 185 pm Praseodymium (Pr): 185 pm Neodymium (Nd): 185 pm Promethium (Pm): 185 pm Samarium (Sm): 185 pm Europium (Eu): 185 pm Gadolinium (Gd): 180 pm Terbium (Tb): 175 pm Dysprosium (Dy): 175 pm Holmium (Ho): 175 pm Erbium (Er): 175 pm Thulium (Tm): 175 pm Ytterbium (Yb): 175 pm Lutetium (Lu): 175 pm Hafnium (Hf): 155 pm Tantalum (Ta): 145 pm Tungsten (W): 135 pm Rhenium (Re): 135 pm Osmium (Os): 130 pm Iridium (Ir): 135 pm Platinum (Pt): 135 pm Gold (Au): 135 pm Mercury (Hg): 150 pm Thallium (Tl): 190 pm Lead (Pb): 180 pm Bismuth (Bi): 160 pm Polonium (Po): 190 pm Astatine (At): 127 pm Radon (Rn): 120 pm Francium (Fr): 260 pm Radium (Ra): 215 pm Actinium (Ac): 195 pm Thorium (Th): 180 pm Protactinium (Pa): 180 pm Uranium (U): 175 pm Neptunium (Np): 175 pm Plutonium (Pu): 175 pm Americium (Am): 175 pm Curium (Cm): 176 pm Period
96 of 118 elements have a measured value.25 – 260 pm

Highest

  1. 1Cs Cesium260
  2. 2Fr Francium260
  3. 3Rb Rubidium235
  4. 4K Potassium220
  5. 5Ba Barium215

Lowest

  1. 1H Hydrogen25
  2. 2He Helium31
  3. 3Ne Neon38
  4. 4F Fluorine50
  5. 5O Oxygen60

22 elements have no measured value for this property, so they are left out of the plot rather than drawn as zero. Almost all of them are synthetic elements that have never existed in weighable quantities.

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