Which of the following pair is are isobars?

(i)

(ii)

Give reasons for your choice.

The atomic species A and B have different number of protons but the same number of nucleons. On the other hand, the atomic species X and Y have the same number of protons but different number of nucleons. Which pair is an example of isobars? Why?

Composition of the nuclei of two atomic species A and B is given as under:

Give the mass numbers of A and B. What is the relation between the two species and which element or elements they represent?

The number of protons, neutrons and electrons in particles A to E are given below:

Give reasons, find a pair of isotopes from the above particles.

The composition of two atomic particles is given below:

(i) What is the mass number of X?

(ii) What is the mass number of Y?

(iii) What is the relation between X and Y?

(iv) Which element/elements do they represent?