first of all yes we do know what an atom looks like and we do have pics to prove it ( even though the atom is smaller than the wavelenth of light) using a scaning elctron microscope

second of all we do know that there are things smaller than atoms for two reasons 1: electorns are smaller than the atom as a whole 2: electrons protons and newtrons are all made of quarks

now reffering to the second part why oh why do you think that these things would fall into a blackhole the same way that a apple or your head would .

and as for the orginal statment NO by definition and my understanding of magnetic feilds a black hole can not have a magnetic field