Size of the Elements on the Periodic Table

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Size of the Elements on the Periodic Table

Periodic table showing the relative sizes of the elements based on atomic radius data.
Periodic table showing the relative sizes of the elements based on atomic radius data. Todd Helmenstine

This special periodic table shows the relative size of atoms of periodic table elements based on atomic radius data. Each atom is shown relative to the largest atom, cesium. You can download the table as a PNG image file if you would like to use it as a periodic table wallpaper. A PDF version of the table is available for printing.

Atomic Radius Trend on the Periodic Table

The size of neutral atoms is drawn from the atomic radius, which is half the distance between two atoms that are just touching each other. If you look at the table, you can see there is a clear trend in atomic radius. Atomic radius is one of the ​periodic properties of the elements.

  • As you move down an element group (column), the size of atoms increases. This is because each atom further down the column has more protons and neutrons and also gains an additional electron energy shell.
  • As you move across an element period (row), the overall size of atoms decreases slightly. Even though atoms further to the right have more protons, neutrons, and electrons, the outer electron shell is the same. The increased number of protons exerts a stronger positive charge, pulling the electrons in toward the nucleus.

Easy-To-Use Chart of Periodic Table Trends