Scale: 10^-12 meters = 1 pm = 1 picometer

Within the Electron Cloud

The tiny dot in the center of this image is the nucleus of the carbon atom. We no longer see the clouds of electron charge because we are now inside the p shell of the carbon atom. When physicists were studying how atoms were constructed, high energy beams of alpha particles were aimed at thin sheets of metal. Most of the particles went straight through the target. Occasionally, though, an alpha particle would be reflected sharply back toward the incoming stream. These results indicated that the positive charge of the atom was concentrated in a minute core at the center of the atom. Most of the charged alpha particles went straight through the target because they were traveling too fast to be affected by the positively charged protons in the nucleus. Those few particles that came close to the nucleus, however, would be reflected at sharp angles.