One of the deductions from Rutherford's alpha particle scattering experiment is that?

Step 1: Analyze the question The question asks what Rutherford's alpha particle scattering experiment showed. Each option is a true fact about atoms, but only one was actually deduced from this experiment.

Step 2: The concept Rutherford (with Geiger and Marsden) fired alpha particles (positively charged helium nuclei) at a very thin gold foil. They observed:

• Most alpha particles passed straight through. This shows that most of the atom is empty space.
• A few were deflected at large angles. This shows that something small, dense and positively charged is in the atom. Like charges repel, so positive alpha particles were repelled by a positive center.
• A very few (about 1 in 8000) bounced almost straight back. This shows that the positive charge and most of the mass are concentrated in a tiny region, which he called the nucleus.

Step 3: Evaluate the options

• A. Electrons are negatively charged: This was established earlier by J.J. Thomson's cathode ray experiments, not by Rutherford's.
• B. Electrons have negligible mass: Also comes from Thomson's work and later measurements, not from this experiment.
• C. Nuclei of atoms are positively charged: Correct. The deflection and back-scattering of positive alpha particles could only be explained by a positively charged nucleus.
• D. Protons are positively charged: Protons were identified later (Rutherford named them around 1919 through other experiments). The scattering experiment itself showed a positive nucleus, not individual protons.

Step 4: Answer

Tip: Link each scientist to their key discovery:

• Thomson → electron (plum pudding model)
• Rutherford → nucleus (gold foil experiment)
• Chadwick → neutron
• Bohr → energy levels

If the question mentions "alpha scattering" or "gold foil", think positive nucleus, empty space.