The radius of a hydrogen atom is:

The radius of a hydrogen atom is 0.037 nm.
An atom is the smallest unit of any element that takes part in a chemical reaction. Atoms are extremely small in size. They are so small that they cannot be seen even under a microscope. The size of an atom is indicated in terms of radius called atomic radius which is measured in nanometers. 1 nanometer is equal to ${10}^{-9}$ meters. The atomic radius of a hydrogen atom is 0.037nm.