Define atomic (covalent) radius. - Leaving Cert Chemistry - Question 1(a) - 2007

The atomic (covalent) radius is defined as half the intermolecular distance, which is the distance between the centers of two atoms bonded together. This measurement specifically applies to atoms in a single homonuclear bond, where both atoms are of the same element.

In a simple representation, if we consider two atoms bonded together, the atomic radius can be expressed as:

$r = \frac{d}{2}$

where:

• $r$ is the atomic radius,
• $d$ is the distance between the centers of the two atoms.