Isotopes have

Options

A. Same number of protons
B. Same number of neutrons
C. Different number of electrons
D. Different atomic numbers

Answer

### Step-by-Step Solution:

1. **Understanding Isotopes**:
- Isotopes are defined as atoms of the same element that have the same number of protons but different numbers of neutrons. This leads to different mass numbers for the isotopes.

2. **Identifying Key Terms**:
- **Atomic Number (Z)**: The number of protons in the nucleus of an atom, which determines the element.
- **Mass Number**: The total number of protons and neutrons in the nucleus.

3. **Analyzing the Options**:
- **Option A: Same number of protons**: This is true for isotopes because they are defined as having the same atomic number.
- **Option B: Same number of neutrons**: This is false because isotopes differ in the number of neutrons.
- **Option C: Different number of electrons**: This is also false because in a neutral atom, the number of electrons equals the number of protons.
- **Option D: Different atomic number**: This is false since isotopes of an element have the same atomic number.

4. **Conclusion**:
- The only correct statement regarding isotopes is that they have the same number of protons. Therefore, the correct answer is **Option A**.