How Small Is A Single Atom?

a bit tricky to answer here, 

 but believe me they are small, have a look here for a better understanding than I can give, so I was amazed to see that a photograph had been made of one, well that has been done before, but not with a normal camera! 

and here is a closer look, using an ordinary camera, with the help of long exposure, a laser, and two electrodes to suspend the atom in the air, David Nadlinger successfully took a photo of a glowing atom, the image won first prize in a science photo contest conducted by UK based Engineering and Physical Sciences Research Council (EPSRC), the EPSRC explains how a single atom is somehow visible to a normal camera, when illuminated by a laser of the right blue-violet colour, the atom absorbs and re-emits light particles sufficiently quickly for an ordinary camera to capture it in a long exposure photograph, image Credit: DAVID NADLINGER/UNIVERSITY OF OXFORD/EPSRC, what an amazing photograph.