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Friday, 9 October

NEET UG 2025 · Chemistry · Question 50

NEET 2025 Chemistry, question 50

Question 50 of the NEET 2025 paper (code 45) is a Chemistry question from Structure of Atom. Its idea, Single-Electron Species Energy Exception, was asked 3 times, in 2024 and 2025, across NEET 2017–2026. The NTA final answer key gives option 1.

Updated 2026-10-08

Q50 · Chemistry

Energy and radius of first Bohr orbit of He+He^+ and Li2+Li^{2+} are

[Given RH=2.18×10−18R_H = 2.18\times10^{-18} J, a0a_0 = 52.9 pm]

  1. 1En(Li2+)=−19.62×10−18E_n(Li^{2+}) = -19.62\times10^{-18} J; rn(Li2+)r_n(Li^{2+}) = 17.6 pm; En(He+)=−8.72×10−18E_n(He^+) = -8.72\times10^{-18} J; rn(He+)r_n(He^+) = 26.4 pmOfficial answer
  2. 2En(Li2+)=−8.72×10−18E_n(Li^{2+}) = -8.72\times10^{-18} J; rn(Li2+)r_n(Li^{2+}) = 26.4 pm; En(He+)=−19.62×10−18E_n(He^+) = -19.62\times10^{-18} J; rn(He+)r_n(He^+) = 17.6 pm
  3. 3En(Li2+)=−19.62×10−16E_n(Li^{2+}) = -19.62\times10^{-16} J; rn(Li2+)r_n(Li^{2+}) = 17.6 pm; En(He+)=−8.72×10−16E_n(He^+) = -8.72\times10^{-16} J; rn(He+)r_n(He^+) = 26.4 pm
  4. 4En(Li2+)=−8.72×10−16E_n(Li^{2+}) = -8.72\times10^{-16} J; rn(Li2+)r_n(Li^{2+}) = 17.6 pm; En(He+)=−19.62×10−16E_n(He^+) = -19.62\times10^{-16} J; rn(He+)r_n(He^+) = 17.6 pm

Official answer: option 1 · NTA final answer key

Same idea

Single-Electron Species Energy Exception, in other papers

NEET asked this idea 3 times, in 2024 and 2025. The other 2 questions below.

  • 2025 Q46The ratio of the wavelengths of the light absorbed by a Hydrogen atom when it undergoes n=2→n=3n = 2 \to n = 3 and n=4→n=6n = 4 \to n = 6…Numerical · Medium
  • 2024 Q57The energy of an electron in the ground state (n = 1) for He+^+ ion is −x-x J, then that for an electron in n = 2 state for Be3+^{3+} ion…Numerical · Medium

Single-Electron Species Energy Exception: every question and how it was framed

The chapter

Structure of Atom in ten years of NEET

16 questions from 2017–2026, asked in 10 of 10 papers, about 1.5 a paper. Quantum Numbers alone had 16.

Chapter analysisStudy this chapterPractise this chapter

Structure of Atom: questions per paper

0241’171’182’191’202’212’222’232’242’251’26