Rutherford's Gold Foil Experiment Reveals Nuclear Charge

Steps:

• Alpha particles pass through foil undeflected, showing atoms consist mostly of empty space.
• Rare large-angle deflections occur due to strong electrostatic repulsion from a tiny, positively charged core.
• This core, the nucleus, must carry the atom's positive charge to cause such repulsions with alpha particles.
• The nuclear model requires protons for charge and neutrons for mass, explaining the observations.

Why D is correct:

• Large deflections from Coulomb repulsion confirm the nucleus holds positive charge (protons) and neutral mass contributors (neutrons) per the nuclear model.

Why the others are wrong:

• A: Describes atomic structure, not a direct nuclear fact.
• B: Infers small size from deflection rarity, but not the primary conclusion.
• C: Relates to density from scattering, but experiment focuses on charge concentration.

Final answer: D