The number of protons and neutrons for most stable elements is

Options

A. Even-odd
B. Even-even
C. Odd-odd
D. Odd-Even

Explanation

To determine the number of protons and neutrons for the most stable elements, we can analyze the relationship between these subatomic particles and the stability of the elements.

### Step-by-Step Solution:

1. **Understanding Stability in Elements**:
- Stable elements are those that do not undergo radioactive decay. They are abundant in nature and have a balanced ratio of protons and neutrons.

2. **Identifying Nucleons**:
- Protons and neutrons together are referred to as nucleons. The stability of an element is influenced by the total number of nucleons.

3. **Even and Odd Nucleons**:
- Research and observations in nuclear chemistry indicate that elements with even numbers of both protons and neutrons tend to be more stable than those with odd numbers. This is due to pairing effects in nuclear forces.

4. **Examples of Stable Elements**:
- Consider helium (He), which has 2 protons and 2 neutrons (both even). It is a stable element.
- Another example is neon (Ne), which has 10 protons and 10 neutrons (again, both even). Neon is also stable.

5. **Conclusion**:
- Based on the analysis and examples, we conclude that the most stable elements typically have an even number of protons and an even number of neutrons.

### Final Answer:
The number of protons and neutrons for most stable elements is **even-even**.