Riz wrote:most of an atom is empty space, so while you're sitting at your computer remember that it, the chair you're sitting on, and even you, are mostly not there.
It's actually stranger than that. Protons, neutrons, and electrons are indeed very much smaller than atoms (the nucleus compared to the whole atom is like a marble in the middle of a sports arena, where the marble weighs more than a thousand times as much as the arena), but the electrons do not occupy discrete locations such that the majority of the atom's volume can properly be said to be empty. Instead, electrons occupy clouds of probability
that intersect, overlap, and occupy the volume of atoms. In molecules, those clouds interact to form interatomic bonds.