The covalent radius of a hydrogen atom, given that the distance between the two nuclei in an H2 molecule is 0.74 angstrom, is:

1. Covalent radius is half the distance between the nuclei of two bonded atoms of the same element. 2. Internuclear distance in H2 is 0.74 angstrom. 3. Covalent radius $= \dfrac{0.74}{2} = 0.37$ angstrom. Taking the full internuclear distance gives 0.74, but the radius is only half of it. _Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 8 Periodic Classification of Elements "Atomic Radius", p.116_