No room is left at the bottom. A team of physicists has shown how a common type of electron microscope can spot single hydrogen atoms — the smallest atoms of them all.  http://louis4j4sheehan4esquire.blogspot.com

Previously, electron microscopes had trouble imaging single atoms lighter than carbon.

http://louis4j4sheehan4esquire.blogspot.com  The University of California, Berkeley team visualized defects and impurities — including atoms of hydrogen— on graphene, the one-atom-thick,