The correct answer is the Helium nucleus.
- Helium nucleus was the source of alpha particles in the Rutherford scattering experiment.
- Ernest Rutherford, a British scientist conducted an experiment and proposed the atomic structure of elements.
Key Points
- Rutherford conducted an experiment by bombarding a thin sheet of gold with α-particles.
- He then analysed the trajectory of these particles after their interaction with the gold foil.
- Since very few α-particles were deflected back, and only a few α-particles had nearly 180o angle of deflection.
- Hence he concluded that the volume occupied by the positively charged particles in an atom is very small as compared to the total volume of an atom.

