I should have said 1.1 km away, as 2.2 km would be the diameter on this scale. You are of course quite right. The atomic diameter is the distance between adjacent nuclei and the electrons could indeed be anywhere. The term electron "orbitals" is I think confusing as it suggests it is similar to planets orbiting the sun. In fact the orbitals are mathematical functions which allow the probability of an electron being in a particular region to be calculated. For GCSE this would be too complicated for most students and the main thing is just to give some idea of the scale.