There is a limit to the precision of a position measurement of any particle, and atoms are made of many particles. The Heisenberg Uncertainty Principle states t

There is a limit to the precision of a position measurement of any particle, and atoms are made of many particles. The Heisenberg Uncertainty Principle states that the uncertainty of the position and momentum of a particle are related. In particular, the product of the errors has a constant lower bound. Visually, if you think of (1d) position and (1d) momentum plotted on a 2d graph, then Heisenberg's principle means that particles are not points, but rectangles with a minimum area.