Atomic radius defines the size of an atom.
Step-by-step explanation:
Atomic radius is defined as “one-half the distance between the nuclei of two identical atoms that are bonded together.” If ‘r’ is the atomic radius and ‘d’ the distance in between nuclei of two atoms that are identical and bonded, then r = d/2.
The units used to express atomic radius are picometer, nanometer, and Angstroms.
In the periodic table, the atomic radius of elements decreases with elements across a period (left-right) and increases with elements down a group.