A natural phenomenon that supports the experimental conclusion that atoms are divis­ ible is

Options

A. allotropy
B. radioactivity
C. cracking
D. none of these

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks for a natural phenomenon that supports the conclusion that atoms are divisible.

2. **Understanding Atomic Structure**: Atoms were once thought to be indivisible. However, scientific discoveries have shown that they can be broken down into smaller particles.

3. **Recognizing Radioactivity**: One of the key natural phenomena that demonstrate the divisibility of atoms is radioactivity.

4. **Explaining Radioactivity**: Radioactivity involves the emission of energy particles from unstable atomic nuclei. This process occurs when an unstable nucleus transforms into a more stable one.

5. **Types of Emitted Particles**: During radioactivity, different types of particles can be emitted, including alpha particles, beta particles, and gamma rays.

6. **Formation of New Elements**: As a result of this emission, the unstable nucleus can change into a different element, indicating that the original atom has been altered, thus supporting the idea that atoms are divisible.

7. **Example of Radioactivity**: For instance, consider an isotope of oxygen (with atomic number 8). When it undergoes radioactive decay, it may emit beta particles and transform into nitrogen, which is a stable element. This transformation illustrates the concept of atomic divisibility.

8. **Conclusion**: Therefore, the natural phenomenon that supports the conclusion that atoms are divisible is radioactivity.

**Final Answer**: Radioactivity.

---