Arrange the following nuclei in the decreasing order of their binding energy per nucleon
A. \( {}^{7}\mathrm{Li} \)
B. \( {}^{16}\mathrm{O} \)
C. \( {}^{4}\mathrm{He} \)
D. \( {}^{238}\mathrm{U} \)
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B, D, C, A
The binding energy per nucleon rises steeply for light nuclei, reaches about 8.8 MeV near A = 56 and then falls slowly for heavy nuclei. \( {}^{4}\mathrm{He} \) is an exceptionally stable nucleus, well above its light neighbours such as \( {}^{7}\mathrm{Li} \).
\( \text{(B) } {}^{16}\mathrm{O}: \approx 7.98\,\mathrm{MeV} \)
\( \text{(D) } {}^{238}\mathrm{U}: \approx 7.57\,\mathrm{MeV} \)
\( \text{(C) } {}^{4}\mathrm{He}: \approx 7.07\,\mathrm{MeV} \)
\( \text{(A) } {}^{7}\mathrm{Li}: \approx 5.61\,\mathrm{MeV} \)
The decreasing order is B, D, C, A.
NCERT (2026-27):
Nuclear Binding Energy – “… Figure 13.1 is a plot of the binding energy per nucleon Ebn versus the mass number A for a large number of nuclei.”
Nuclear Binding Energy – “… (ii) Ebn is lower for both light nuclei (A<30) and heavy nuclei (A>170).”
