Which of the statement with regard to Isotopes and Isobars is/are correct ?
1. Isotopes have same mass number.
2. Isobars have same atomic number.
Select the correct answer using the code given below :

Options

A. 1 only
B. 2 only
C. Both 1 and 2
D. Neither 1 nor 2

Answer

To solve the question regarding isotopes and isobars, we need to analyze the definitions and properties of both terms.

### Step-by-Step Solution:

1. **Understanding Isotopes**:
- Isotopes are atoms of the same element that have the same atomic number (number of protons) but different mass numbers (total number of protons and neutrons).
- Example: Carbon-12 (6C12) and Carbon-13 (6C13) are isotopes of carbon. They both have the same atomic number (6) but different mass numbers (12 and 13).

**Hint**: Remember that isotopes differ in mass number but share the same atomic number.

2. **Understanding Isobars**:
- Isobars are atoms of different elements that have the same mass number but different atomic numbers.
- Example: Argon-40 (18Ar40) and Calcium-40 (20Ca40) are isobars. They have the same mass number (40) but different atomic numbers (18 for Argon and 20 for Calcium).

**Hint**: Isobars have the same mass number but differ in atomic number.

3. **Analyzing the Statements**:
- **Statement 1**: "Isotopes have same mass number."
- This statement is incorrect because isotopes have the same atomic number but different mass numbers.
- **Statement 2**: "Isobars have same atomic number."
- This statement is also incorrect because isobars have the same mass number but different atomic numbers.

4. **Conclusion**:
- Both statements provided in the question are incorrect.
- Therefore, the correct answer is that neither statement 1 nor statement 2 is correct.

### Final Answer:
The correct answer is: Neither 1 nor 2.

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