What caused the deflection of the alpha particles in Rutherford's gold foil experiment?

Answer 1

The alpha particles scatter from the atomic nuclei in the gold foil. The repulsive electrostatic force between the nucleus and the alpha particle (because both are positively charged and like charges repel) deflects the alpha particle. Because of the large mass and (relatively) large energy of the alpha particles in Rutherford scattering experiments, the alpha particles are largely unaffected by the electrons in the gold atoms. More accurately, the scattering of the alpha particles from the electrons produces small angular deflections.

Because the nucleus is small -- approximately 1/10000th the size of the whole atom -- most of the time the alpha particles will pass through the atom with little or no deflection. But occasionally, the alpha particles will start on a trajectory that, without the electrostatic deflection, would take them very close to the nucleus. In such cases, the electrostatic force produces a large angular deflection and can even scatter the alpha particles backwards. If the positive charge in the atom were distributed over the entire size of the atom, the likelihood of having such a large-angle scattering would be much smaller than it was (is) observed to be. Thus, the original experiments demonstrated that the positive charge in atoms is confined to a small region at the very center of an atom. Indeed, the data also provided an estimate of the size of the nucleus. More advanced analyses of such scattering experiments with modern equipment but using electron beams have provided detailed measurements of nuclear diameters for a wide range of atomic nuclei.

Answer 2

A zinc sulfide coated screen surrounding the gold foil produced a flash of light whenever it was struck by an alpha particle. By noting where the flash occurred, the scientists could determine if the atoms in the gold foil deflected the alpha particles.

Answer 3

The results of the gold foil test was that the alpha particles in the beam began to spread out as they passed through the foil. This reaction became known as Rutherford Scattering.

Answer 4

The cause is the clash between alpha particles and the atomic nucleus.

Answer 5

Positive particles

Answer 6

The gold nuclei.