Which of the following conclusions regarding the structure of atom is based on Rutherford's `alpha`-particle scattering experiment?

Options

A. The positive charge is concentrated in a very small volume of the atom.
B. The positive charge is scattered with the electrons throughout the atom.
C. The volume occupied by the nucleus is half of the volume of atom.
D. Most of the space in the atom is occupied by the neutrons.

Explanation

To determine which conclusion regarding the structure of the atom is based on Rutherford's alpha-particle scattering experiment, we can analyze the options provided:

### Step-by-Step Solution:

1. **Understanding Rutherford's Experiment**:
Rutherford conducted an experiment where alpha particles were directed at a thin gold foil. He observed how these particles were scattered, which led to significant conclusions about the atomic structure.

2. **Analyzing the First Conclusion**:
The first conclusion states that "the positive charge is concentrated in a very small volume of the atom." This is true based on Rutherford's findings. Most alpha particles passed through the foil, but a few were deflected at large angles, indicating a concentrated positive charge in a small region (the nucleus).

3. **Analyzing the Second Conclusion**:
The second conclusion states that "the positive charge is scattered with electrons throughout the atom." This contradicts Rutherford's findings. He concluded that the positive charge is not spread out but rather concentrated in the nucleus.

4. **Analyzing the Third Conclusion**:
The third conclusion states that "the volume occupied by the nucleus is half of the atom." This is incorrect. Rutherford's experiment showed that the nucleus occupies a very small fraction of the total volume of the atom.

5. **Analyzing the Fourth Conclusion**:
The fourth conclusion states that "most of the space in the atom is occupied by the neutron." This is also incorrect. While neutrons are part of the nucleus, they do not occupy most of the space in the atom; rather, the majority of the atom is empty space.

6. **Final Conclusion**:
Based on the analysis, the only conclusion that aligns with Rutherford's findings is the first one: "the positive charge is concentrated in a very small volume of the atom."

### Answer:
The correct conclusion based on Rutherford's alpha-particle scattering experiment is:
**The positive charge is concentrated in a very small volume of the atom.**

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