Multiple choice Radius of hydrogen atom is of the order of _____ . 1 nm 1 A� 1 cm 0.1 A� Reveal answer Fill a bubble to check yourself B Correct answer Explanation The atomic radius of a hydrogen atom is approximately 0.05 nm, which is equivalent to 0.5 Angstroms (A). Among the choices, 1 Angstrom is the closest order of magnitude.