What is the Difference Between Atomic Radius and Ionic Radius?

The main difference between atomic radius and ionic radius lies in the electrical charge of the atoms or ions being considered. Here are the key differences:

• Atomic Radius: This refers to the radius of a neutral atom, which is the distance from the nucleus to the outermost electrons in the neutral atom. Atomic radius is a measure of the size of an atom and can be affected by various factors such as the doubling of atomic radius when crossing a period from left to right in the periodic table.
• Ionic Radius: This refers to the radius of an electrically charged atom, either a cation (positive charge) or an anion (negative charge). The ionic radius can be larger or smaller than the atomic radius depending on the electrical charge of the ion. For example, the ionic radius of a cation is smaller than its atomic radius because the atom loses electrons, reducing the electron orbitals and making the radius smaller. Conversely, the ionic radius of an anion is larger than its atomic radius because the atom gains electrons, increasing the electron orbitals and making the radius larger.

In summary, atomic radius refers to the size of a neutral atom, while ionic radius refers to the size of an electrically charged atom, and their values can be affected by the presence or absence of electrons in the outermost orbitals.

Comparative Table: Atomic Radius vs Ionic Radius

The main difference between atomic radius and ionic radius lies in the arrangement of electrons and the charge of the atom or ion. Here is a comparison table highlighting the differences:

For example, the atomic radius of sodium (Na) is 0.102 nm, while its ionic radius as a sodium ion (Na+) is 0.102 nm. Conversely, the atomic radius of fluorine (F) is 0.071 nm, but its ionic radius as a fluoride ion (F-) is 0.133 nm.