JEE Main Chemistry · Structure of Atom

Bohr's Atomic Theory in JEE Main

Name: Bohr's Atomic Theory: JEE Main previous year questions
Creator: Lumi

Bohr's Atomic Theory (Chemistry, Structure of Atom) came 15 times in 15 of the 42 JEE Main shifts Lumi analysed, across 8 distinct ideas. 12 of them came in 2024–26; it was last asked in 2026.

Questions: 15; in 15 shifts
Ideas asked: 8; 4 asked more than once
Numerical answer: 6; 40% of its questions
Pattern: Asked most years; last asked 2026

Questions each year

In the shifts Lumi analysed for each year.

Difficulty and format

Easy 11Medium 4Hard 0

Format

Single correct7 Q
Numerical value6 Q
Other2 Q

Ideas inside the topic

8 ideas

Bohr Radius Calculation5 Q
Total, Kinetic, and Potential Energy2 Q
Ionization and Excitation Energy2 Q
Longest and Shortest Wavelengths in a Series2 Q
Limitations of Bohr Model1 Q
Photoelectric Effect Coupling1 Q
Rydberg Formula and Transitions1 Q
Number of Spectral Lines in Transitions1 Q

Where it sits

Part of Structure of Atom, which had 46 questions in all. Bohr's Atomic Theory accounts for 33% of them. In Lumi's JEE taxonomy it belongs to Physical Chemistry.

Every question

All 15 Bohr's Atomic Theory questions

Newest first, each with its options and official answer.

2 Apr 2026, Shift 1 · Q52What is the energy (in $\mathrm{J\ atom^{-1}}$ ) required for the following process ? $\mathrm{Li^{2+}(g)\rightarrow Li^{3+}(g)+e^-}$ (Take…EasySingle correct
2 Apr 2026, Shift 2 · Q71The surface of sodium metal is irradiated with radiation of wavelength $x$ nm. The kinetic energy of ejected electrons is…EasyNumerical value
4 Apr 2026, Shift 1 · Q52What is the ratio of wave number of first line (lowest energy line) of Balmer series of H atomic spectrum to first line of its Brackett…MediumSingle correct
4 Apr 2026, Shift 2 · Q52The species having identical radii according to the Bohr's theory are: A. H (first orbit) B. $\mathrm{He^+}$ (first orbit) C.…EasyOther
6 Apr 2026, Shift 1 · Q52If shortest wavelength of hydrogen atom in Lyman series is $x$ , then longest wavelength in Balmer series of $\mathrm{He^+}$ is:MediumSingle correct
6 Apr 2026, Shift 2 · Q52The Bohr radius of a hydrogen like species is 70.53 pm. The species and the stationary state ( $n$ ) are respectively (Given : Hydrogen atom…EasySingle correct
2 Apr 2025, Shift 1 · Q52According to Bohr's model of hydrogen atom, which of the following statement is incorrect ?EasySingle correct
3 Apr 2025, Shift 1 · Q52Which of the following postulate of Bohr's model of hydrogen atom is not in agreement with quantum mechanical model of an atom?EasySingle correct
8 Apr 2025, Shift 2 · Q72The energy of an electron in first Bohr orbit of H-atom is −13.6 eV. The magnitude of energy value of electron in the first excited state…EasyNumerical value
6 Apr 2024, Shift 2 · Q81For hydrogen atom, energy of an electron in first excited state is $-3.4$ eV, K.E. of the same electron of hydrogen atom is $x$ eV. Value…EasyNumerical value
30 Jan 2024, Shift 2 · Q81Number of spectral lines obtained in $\mathrm{He^+}$ spectra, when an electron makes transition from fifth excited state to first excited…EasyNumerical value
31 Jan 2024, Shift 1 · Q82The ionization energy of sodium in kJ mol $^{-1}$ , if electromagnetic radiation of wavelength 242 nm is just sufficient to ionize sodium…MediumNumerical value
3 Aug 2021, Shift 2 · Q53The ratio of radii for the first and third orbits of hydrogen atom is $1 : x$ . The value of $x$ is $\underline{\hspace{2em}}$ . (Integer…EasyNumerical value
8 Jan 2020, Shift 1 · Q30For the Balmer series in the spectrum of H atom, $\bar{\nu} = R_H\left\{\frac{1}{n_1^2}-\frac{1}{n_2^2}\right\}$ , the correct statements…MediumOther
2 Apr 2017 (offline) · Q38The radius of the second Bohr orbit for hydrogen atom is : (Planck's Const. $h=6.6262\times10^{-34}$ Js; mass of electron…EasySingle correct