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Chemistry · Structure of Atom

JEE Main 2026 — 23 January, Morning Shift — Question 49

Which of the following statements regarding the energy of the stationary state is true in the following one-electron system ?

  1. Option A:

    −1.09×10−18 J-1.09 \times 10^{-18} \mathrm{~J} for second orbit of H atom.

  2. Option B:

    +2.18×10−18 J+2.18 \times 10^{-18} \mathrm{~J} for second orbit of He+\mathrm{He}^{+} ion

  3. Option C:

    +8.72×10−18 J+8.72 \times 10^{-18} \mathrm{~J} for first orbit of He+\mathrm{He}^{+} ion

  4. Option D:

    −2.18×10−18 J-2.18 \times 10^{-18} \mathrm{~J} for third orbit of Li2+\mathrm{Li}^{2+} ion

    Correct

Answer: D

Step-by-step solution

Energy of hydrogen-like species:

\left(\frac{Z^2}{n^2}\right)$$ A) H atom $(Z=1,\ n=2)$ $$E = -2.18 \times 10^{-18} \times \frac{1}{4} = -5.45 \times 10^{-19}$$ B) $\mathrm{He^+}$ $(Z=2,\ n=2)$ $$E = -2.18 \times 10^{-18} \times \frac{4}{4} = -2.18 \times 10^{-18}$$ C) $\mathrm{He^+}$ $(Z=2,\ n=1)$ $$E = -2.18 \times 10^{-18} \times 4 = -8.72 \times 10^{-18}$$ D) $\mathrm{Li^{2+}}$ $(Z=3,\ n=3)$ $$E = -2.18 \times 10^{-18} \times \frac{9}{9} = -2.18 \times 10^{-18}$$ Hence, the only option D matches.

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Paper
23 January, Morning Shift
Subject
Chemistry
Chapter
Structure of Atom
Topic
Analysis of Spectra of H-like species

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