Question

Which of the following is an isobaric pair :

• A. \({}_6^{12}C\) & \({}_6^{13}C\)
• B. \({}_1^3 H\) & \({}_2^3 He\)
• C. \({}_7^{14} N\) & \({}_2^4 He\)
• D. \({}_8^{16} O\) & \({}_7^{14} N\)

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
We need to identify the pair of atomic nuclei from the given options that are isobars.
Step 2: Key Formula or Approach:
The definition of isobars is crucial here. Isobars are atoms (nuclides) of different chemical elements that have the same number of nucleons. In other words, they have the same mass number (A) but different atomic numbers (Z). The notation used is \({}_Z^A X\), where A is the mass number and Z is the atomic number.
Step 3: Detailed Explanation:
Let's analyze each option based on the definition:
- (A) \({}_6^{12}C\) & \({}_6^{13}C\):
- Same atomic number (Z=6).
- Different mass numbers (A=12 and A=13).
- These are isotopes of Carbon.
- (B) \({}_1^3 H\) & \({}_2^3 He\):
- Different atomic numbers (Z=1 for Hydrogen, Z=2 for Helium).
- Same mass number (A=3).
- This pair fits the definition of isobars.
- (C) \({}_7^{14} N\) & \({}_2^4 He\):
- Different atomic numbers (Z=7 and Z=2).
- Different mass numbers (A=14 and A=4).
- These are neither isobars nor isotopes.
- (D) \({}_8^{16} O\) & \({}_7^{14} N\):
- Different atomic numbers (Z=8 and Z=7).
- Different mass numbers (A=16 and A=14).
- These are neither isobars nor isotopes.
Step 4: Final Answer:
The only pair that has the same mass number but different atomic numbers is \({}_1^3 H\) and \({}_2^3 He\). Therefore, they are an isobaric pair.