Which of the following pair of nuclei are isobars of the element?

Step-by-step solution

Isobars are atoms of different chemical elements that have the same number of nucleons (mass number A ), but different atomic numbers ( Z ). In the given options: (1) ₁^3 H and ₂^3 He : Both have the same mass number A = 3 . Since they have different atomic numbers ( Z=1 and Z=2 ), they are isobars. (2) ₁^2 H and ₁^3 H : These have the same atomic number ( Z=1 ) but different mass numbers. They are isotopes. (3) ₈₀¹⁹⁸ Hg and ₇₉¹⁹⁷ Au : These have different mass numbers ( 198 and 197 ). (4) ₉₂²³⁶ U and ₉₂²³⁸ U : The