Ionic Radius Calculator

Explore ionic radii and understand how atom size changes when electrons are gained or lost.

Na+

Sodium

Cation (+1)

102 pm

Shannon Ionic Radius (CN=6)

Picometers

102 pm

Angstroms

1.02 A

Nanometers

0.102 nm

Comparison with Neutral Atom

Na

Neutral

190 pm

Na+

Ion

102 pm

Size Change:

-88 pm (-46.3%)

Ionic Radius Trends

  • Cations: Smaller than parent atom (fewer electrons, same nuclear charge)
  • Anions: Larger than parent atom (more electrons, increased repulsion)
  • Isoelectronic series: More protons = smaller radius