The typical size of atoms and small molecules is around 1 × 10-10 m (0.1 nm). For example: diameter of a hydrogen atom, H 1.0 × 10-10 m width of a hydrogen molecule, H 2 2.9 × 10-10 m ...

An atom of hydrogen is made up of an electron orbiting ... in Switzerland measured the radius of a proton in muonic hydrogen and found it was smaller than previously thought.