Arrange the following elements in the ascending order of their bindin…

The correct answer is Option (1) → C, D, B, A

The binding energy per nucleon rises steeply for light nuclei, reaches its maximum of about 8.8 MeV near A = 56 (iron), and then falls slowly for heavier nuclei. So very light and very heavy nuclei both have lower values. Typical values:

    \( \text{(C) } {}^{14}\mathrm{N}: \text{ about } 7.5\,\mathrm{MeV} \)
    \( \text{(D) } {}^{238}\mathrm{U}: \text{ about } 7.6\,\mathrm{MeV} \)
    \( \text{(B) } {}^{100}\mathrm{Mo}: \text{ about } 8.6\,\mathrm{MeV} \)
    \( \text{(A) } {}^{56}\mathrm{Fe}: \text{ about } 8.8\,\mathrm{MeV} \)

So the ascending order is (C), (D), (B), (A).

NCERT (2026-27):
Nuclear Binding Energy – “… Figure 13.1 is a plot of the binding energy per nucleon E_bn versus the mass number A for a large number of nuclei. We notice the following main features of the plot: (i) the binding energy per nucleon, E_bn, is practically constant, i.e. practically independent of the atomic number for nuclei of middle mass number ( 30 < A < 170). The curve has a maximum of about 8.75 MeV for A = 56 and has a value of 7.6 MeV for A = 238. (ii) E_bn is lower for both light nuclei (A<30) and heavy nuclei (A>170).”