The isotopes of an element have

Options

A. same atomic numbers
B. same atomic weights
C. different atomic numbers
D. different chemical properties.

Answer

To solve the question regarding the characteristics of isotopes, we can follow these steps:

### Step 1: Understand the Definition of Isotopes
Isotopes are variants of a particular chemical element that have the same number of protons (atomic number) but different numbers of neutrons, resulting in different mass numbers.

### Step 2: Identify Key Characteristics of Isotopes
- **Same Atomic Number**: Isotopes of an element have the same atomic number, which means they belong to the same element.
- **Different Mass Numbers**: Due to the difference in the number of neutrons, isotopes have different mass numbers.
- **Similar Chemical Properties**: Isotopes of an element exhibit the same chemical properties because they have the same electronic configuration.

### Step 3: Analyze the Options Given in the Question
1. **Same Atomic Number**: This is correct.
2. **Same Atomic Weight**: This is incorrect because isotopes have different mass numbers (and thus different atomic weights).
3. **Different Atomic Number**: This is incorrect; isotopes have the same atomic number.
4. **Different Chemical Properties**: This is incorrect; isotopes have similar chemical properties.

### Step 4: Conclusion
Based on the analysis, the correct characteristic of isotopes is that they have the same atomic number.

### Final Answer
The isotopes of an element have the same atomic number.

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