All nuclides exhibit radioactivity when the atomic number exceeds

Options

A. 80
B. 83
C. 90
D. 92

Explanation

To solve the question regarding the atomic number at which all nuclides exhibit radioactivity, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Atomic Number (Z)**:
- The atomic number (Z) is defined as the number of protons in the nucleus of an atom. It also equals the number of electrons in a neutral atom.

2. **Defining Radioactivity**:
- Radioactivity is a process by which unstable atomic nuclei lose energy by emitting radiation. This can occur through alpha decay, beta decay, or gamma decay. The goal of these processes is to achieve a more stable nuclear configuration.

3. **Identifying the Threshold for Radioactivity**:
- It is known from nuclear chemistry that elements with higher atomic numbers tend to be unstable due to the increasing ratio of neutrons to protons. As the atomic number increases, the forces that hold the nucleus together become less effective, leading to instability.

4. **Determining the Critical Atomic Number**:
- Research and empirical data indicate that all nuclides with an atomic number greater than 83 are radioactive. This means that elements with Z > 83 will exhibit radioactivity.

5. **Conclusion**:
- Therefore, the answer to the question is that all nuclides exhibit radioactivity when the atomic number exceeds 83.

### Final Answer:
All nuclides exhibit radioactivity when the atomic number exceeds **83**.

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