Question

In Rutherford's experiment, a thin gold foil was bombarded with alpha particles. If 'Thomson's Plum-Pudding' model of the atom was applicable, then what should have happened?

• A. All the alpha particles would have been deflected by the foil.
• B. All the alpha particles should have bounced straight back from the foil.
• C. Alpha particles should have passed through the foil with little or no deflection.
• D. Alpha particles should have become embedded in the foil.

Answer 1

The correct option is C Alpha particles should have passed through the foil with little or no deflection.

According to 'Thomson's Plum-Pudding' model, a positive charge is spread over a sphere in which the electrons are embedded to make the atom as a whole neutral. If $\alpha$-particles were bombarded over this charge-neutral sphere, $\alpha$-particles should have passed through the foil with a little deflection or straight because $\alpha$ particles are positively charged ($H{e}^{2+}$) particles and they would have experienced no net force on them as the charge would have been uniformly spread, but that wasn't the case and the alpha particles were deflected, disapproving Thomas' model of the atom.