Question

Which of the following is a pair of Isobar?
(A) ${}_7{N^{15}},{}_8{O^{16}}$
(B) ${}_6{C^{13}},{}_7{N^{13}}$
(C) ${}_6{C^{13}},{}_7{N^{14}}$
(D) ${}_7{N^{13}},{}_8{O^{15}}$

Answer 1

Hint: Before doing any questions of isobar firstly we know that what isobar is so, isobar are those elements whose atomic number is different but atomic mass is same that type of elements are known as isobars in this question we can easily find the pair of isobars by using the above property. Whereas it is clear from the definition that only we have to focus on only two things of any element which are atomic mass and atomic number.

Complete Step by Step Solution:
Before going ahead we just know about what is atomic number and what is atomic mass,
So, the number of nucleons present in the centre of the atom called nucleus is known by the name of atomic number.

And the sum of the number of protons and neutrons present in the atom are called by the name of atomic mass.

 As in the above given there is only one option where the atomic number of both elements are different but atomic mass is same.
So, the answer is ${}_6{C^{13}},{}_7{N^{13}}$ .
Hence, the correct option is (B).

Note: We talked about isobars but as in this a similar topic is also there named as isotopes so what is isotopes, isotopes are those elements whose atomic number is same but atomic mass is different they are called isotopes. By reading both term definitions we get that isotopes are fully opposite to isobars.