Final answer:
The bonding atomic radius of iodine in an I2 molecule is 133 picometers (1.33 angstroms), which is derived from half the internuclear distance of 2.66 angstroms (266 picometers) separating two iodine atoms in the molecule.
Step-by-step explanation:
The bonding atomic radius of the element iodine in an I2 molecule can be calculated by taking half the distance between the nuclei of the two iodine atoms. Given that the internuclear distance in I2 is 2.66 angstroms (Å), which equals 266 picometers (pm), the atomic radius would be half of this value.
Using the established approach for determining atomic radii through covalent bonds, as shown for diatomic molecules like Cl2 and H2, we divide the distance by two to find that the atomic radius of an iodine atom in an I2 molecule is 266 pm / 2, which is 133 picometers (1.33 Å).