What is radius of the hydrogen atom?

The radius of the hydrogen atom is approximately 0.053 nanometers (nm). This value is based on the Bohr model of the hydrogen atom, which assumes that electrons move in circular orbits around the nucleus. However, this model has been replaced by the more accurate quantum mechanical model, which describes the electron's location in terms of probability distributions rather than well-defined orbits. In the quantum mechanical model, the radius of the hydrogen atom is not fixed but rather varies depending on the electron's energy level. Nonetheless, the Bohr model is still useful in providing a simplified explanation of the properties of hydrogen.