The curve of blinding energy per nucleon as a function of atomic mass number has a sharp peak for helium nucleus. This implies that helium.

Options

A. can easily be broken up
B. is very stable
C. can be used as fissionable material
D. is radioactive

Explanation

To solve the question regarding the binding energy per nucleon and its implications for the helium nucleus, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Binding Energy per Nucleon**:
- The binding energy per nucleon is a measure of the stability of a nucleus. It indicates how much energy is required to remove a nucleon from the nucleus. A higher binding energy per nucleon means a more stable nucleus.

2. **Analyzing the Curve**:
- The question mentions a curve of binding energy per nucleon as a function of atomic mass number (A). This curve typically shows that as we move from lighter to heavier nuclei, the binding energy per nucleon increases, reaches a peak, and then starts to decrease for very heavy nuclei.

3. **Identifying the Peak for Helium**:
- The sharp peak for helium indicates that it has a significantly higher binding energy per nucleon compared to its neighboring nuclei (like hydrogen and lithium). This sharp peak suggests that helium is particularly stable.

4. **Implications of Stability**:
- Since helium has a high binding energy per nucleon, it implies that helium nuclei are tightly bound and thus very stable. This stability means that helium is less likely to undergo radioactive decay or fission.

5. **Conclusion**:
- Therefore, the implication of the sharp peak in the binding energy per nucleon curve for helium is that helium is very stable compared to its neighboring elements. It does not easily break apart, and it is not a fissionable material.

### Final Answer:
Helium is very stable compared to its neighboring nuclei due to its high binding energy per nucleon, as indicated by the sharp peak in the binding energy curve.

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