In this same context, a typical bacterium would be about 50 yards long, and the average human cell about the size of a football stadium. While these pictures give you some idea of the size of individual entities and their static relationship to one another, the most extraordinary aspect of this situation doesn't appear until you examine the movement of the molecules. If you speeded up everything in relationship to their size, at body temperature all these substances would be moving very rapidly. For example, the baseballs would be coursing around at the amazing speed of millions of miles per hour. The small molecules even faster.
Elements combine to form compounds.
Atoms combine to form molecules. Two charged particles push away one another when their charges are of the same sign and pull toward ones another when they are different. A bond between two atoms is a balance between pulls and pushes. The electrons of an atom can be thought of as residing in shells of clouds which have a certain maximum occupancy. When that occupancy is attained, as in the case of the noble gases, the atom is stable and will not combine with other atoms.