Atomic Radius
| Formula / Notation | r (pm or Å); decreases across period, increases down group |
|---|---|
| Also Known As | Covalent radius; van der Waals radius; ionic radius; atomic size; r_atom |
What is Atomic Radius?
The atomic radius is a measure of the size of an atom, defined as the distance from the nucleus to the outermost electron shell. Because electrons form a probability cloud, atomic radius is typically measured as half the distance between two adjacent identical atoms bonded together (covalent radius) or as the van der Waals radius. Atomic radius decreases across a period and increases down a group.
Formula & Notation
Other Names / Synonyms: Covalent radius; van der Waals radius; ionic radius; atomic size; r_atom
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The atomic radius is a measure of the size of an atom, defined as the distance from the nucleus to the outermost electron shell. Because electrons form a probability cloud, atomic radius is typically measured as half the distance between two adjacent identical atoms bonded together (covalent radius) or as the van der Waals radius. Atomic radius decreases across a period and increases down a group.
Predicting bond lengths and molecular sizes; understanding periodic trends; materials science (crystal structures); computational chemistry; explaining chemical reactivity patterns
No hazard — a physical property of atoms.
The formula or notation for Atomic Radius is: r (pm or Å); decreases across period, increases down group