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Structure of Atom

Previous year questions with solutions · 2025 – 2026

39Questions
31Papers covered
5.47% ↑26.3%Weightage in 2026
’25
’26
Year-wise statistics questions · papers · average per paper · weightage
YearQuestionsPapersAvg / paperWeightage
202626191.45.47% ↑26.3%
202513121.14.33%

39 questions · newest paper first · page 1 of 2

1

Consider two radiations of wavelengths 1. 1 = 2000 Å 2. 2 = 6000 Å The ratio of the energies of these two radiations ( E1E2 ) is (Nearest integer).

JEE Main 2026 (Online) 8th April Evening Shift
2

If shortest wavelength of hydrogen atom in Lyman series is x, then longest wavelength in Balmer series of He+ is:

  1. 9x5
  2. 36x5
  3. x4
  4. 5x9
JEE Main 2026 (Online) 6th April Morning Shift
3

Match the LIST-I with LIST-II

  1. A-IV, B-I, C-III, D-II
  2. A-IV, B-II, C-III, D-I
  3. A-III, B-I, C-IV, D-II
  4. A-IV, B-III, C-II, D-I
JEE Main 2026 (Online) 6th April Morning Shift
4

The Bohr radius of a hydrogen like species is 70.53 pm. The species and the stationary state (n) are respectively (Given : Hydrogen atom Bohr radius is 52.9 pm)

  1. Li2+, 3
  2. He+, 3
  3. He+, 2
  4. Li2+, 2
JEE Main 2026 (Online) 6th April Evening Shift
5

Arrange the following atomic orbitals of multi electron atoms in order of increasing energy. Choose the correct answer from the options given below:

  1. C < D < B < A < E
  2. B < A < E < C < D
  3. E < C < D < B < A
  4. E < B < A < D < C
JEE Main 2026 (Online) 5th April Morning Shift
6

Identify the correct statements from the following : Choose the correct answer from the options given below:

  1. A, B and C Only
  2. A, B and D Only
  3. B, C and D Only
  4. A, C and D Only
JEE Main 2026 (Online) 5th April Morning Shift
7

Which of the following statement(s) is/are true ? Choose the correct answer from the options given below :

  1. A, B and C only
  2. A and C only
  3. C and D only
  4. A only
JEE Main 2026 (Online) 5th April Evening Shift
8

What 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 series?

  1. 5 : 1
  2. 5 : 0.81
  3. 5 : 1.75
  4. 5 : 27
JEE Main 2026 (Online) 4th April Morning Shift
9

Which of the following is correct set of 4 quantum numbers of 19th electron in Chromium (Atomic number = 24) in accordance with Aufbau principle?

  1. n = 3, l = 2, m = +2, s = + 12
  2. n = 3, l = 2, m = -2, s = + 12
  3. n = 4, l = 1, m = 0, s = + 12
  4. n = 4, l = 0, m = 0, s = + 12
JEE Main 2026 (Online) 4th April Morning Shift
10

The species having identical radii according to the Bohr's theory are : Choose the correct answer from the options given below :

  1. A and C Only
  2. A and E Only
  3. B and E Only
  4. C and D Only
JEE Main 2026 (Online) 4th April Evening Shift
11

What is the energy (in J atom-1) required for the following process ? Li2+(g) Li3+(g) + e- (Take the ionization energy for the H atom in the ground state as 2.18 10-18 J atom-1)

  1. 8.72 10-18
  2. 1.962 10-18
  3. 1.962 10-17
  4. 6.54 10-17
JEE Main 2026 (Online) 2nd April Morning Shift
12

The surface of sodium metal is irradiated with radiation of wavelength x nm. The kinetic energy of ejected electrons is 2.8 10-20 J. The work function of sodium is 2.3 eV. The value of x is 102 nm. (Nearest integer) (Given : h = 6.6 10-34 J s; 1 eV = 1.6 10-19 J; c = 3.0 108 m s-1)

JEE Main 2026 (Online) 2nd April Evening Shift
13

The wave numbers of three spectral lines of H atom are considered. Identify the set of spectral lines belonging to Balmer series. (R = Rydberg constant)

  1. 5R36, 3R16, 21R100
  2. 7R144, 3R16, 16R255
  3. 3R4, 3R16, 7R144
  4. 5R36, 8R9, 15R16
JEE Main 2026 (Online) 28th January Morning Shift
14

[figure] Figure 1. electron probability density for 2s orbital [figure] Figure 2. wave function for 2s orbital Which of the following point in Figure 2 most accurately represents the nodal surface as shown in Figure 1?

  1. D
  2. B
  3. C
  4. A
JEE Main 2026 (Online) 28th January Morning Shift
15

The wavelength of photon 'A' is 400 nm. The frequency of photon 'B' is 1016 s-1. The wave number of photon 'C' is 104 cm-1. The correct order of energy of these photons is :

  1. A > C > B
  2. C > B > A
  3. B > A > C
  4. A > B > C
JEE Main 2026 (Online) 28th January Evening Shift
16

Two positively charged particles m1 and m2 have been accelerated across the same potential difference of 200 kV as shown below. [figure] [Given mass of m1 = 1 amu and m2 = 4 amu] The de Broglie wavelength of m1 will be x times of m2. The value of x is (nearest integer)

JEE Main 2026 (Online) 28th January Evening Shift
17

The hydrogen spectrum consists of several spectral lines in Lyman series (L1, L2, L3 ; L1 has lowest energy among Lyman series). Similarly it consists of several spectral lines in Balmer series (B1, B2, B3 ; B1 has lowest energy among Balmer lines). The energy of L1 is x times the energy of B1. The value of x is 10-1. (Nearest integer)

JEE Main 2026 (Online) 24th January Morning Shift
18

The wavelength of spectral line obtained in the spectrum of Li2+ ion, when the transition takes place between two levels whose sum is 4 and difference is 2, is

  1. 1.14 10-6 cm
  2. 2.28 10-6 cm
  3. 1.14 10-7 cm
  4. 2.28 10-7 cm
JEE Main 2026 (Online) 24th January Evening Shift
19

Given, (A) n = 5, ml = -1 (B) n = 3, l = 2, ml = -1, ms = + 12 The maximum number of electron(s) in an atom that can have the quantum numbers as given in (A) and (B) respectively are :

  1. 4 and 1
  2. 2 and 4
  3. 26 and 1
  4. 8 and 1
JEE Main 2026 (Online) 23rd January Morning Shift
20

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

  1. +2.18 10-18 J for second orbit of He+ ion
  2. +8.72 10-18 J for first orbit of He+ ion
  3. -1.09 10-18 J for second orbit of H atom.
  4. -2.18 10-18 J for third orbit of Li2+ ion
JEE Main 2026 (Online) 23rd January Morning Shift
21

The work functions of two metals (MA and MB) are in the 1 : 2 ratio. When these metals are exposed to photons of energy 6 eV, the kinetic energy of liberated electrons of MA : MB is in the ratio of 2.642 : 1. The work functions (in eV) of MA and MB are respectively.

  1. 3.1, 6.2
  2. 1.5, 3.0
  3. 2.3, 4.6
  4. 1.4, 2.8
JEE Main 2026 (Online) 23rd January Evening Shift
22

Identify the INCORRECT statements from the following : Choose the correct answer from the options given below :

  1. A and D Only
  2. A and C Only
  3. A and B Only
  4. B and C Only
JEE Main 2026 (Online) 23rd January Evening Shift
23

The energy required by electrons, present in the first Bohr orbit of hydrogen atom to be excited to second Bohr orbit is J mol-1. Given: RH = 2.18 10-11 ergs.

  1. 9.835 1012
  2. 1.635 10-11
  3. 1.635 10-18
  4. 9.835 105
JEE Main 2026 (Online) 22nd January Morning Shift
24

The energy of first (lowest) Balmer line of H atom is x J. The energy (in J) of second Balmer line of H atom is :

  1. x1.35
  2. 1.35x
  3. x2
  4. 2x
JEE Main 2026 (Online) 22nd January Evening Shift
25

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are true
  2. Statement I is true but Statement II is false
  3. Statement I is false but Statement II is true
  4. Both Statement I and Statement II are false
JEE Main 2026 (Online) 21st January Morning Shift
26

Consider the following spectral lines for atomic hydrogen : The correct arrangement of the above lines in ascending order of energy is :

  1. D < C < A < B
  2. A < B < C < D
  3. D < A < C < B
  4. C < D < B < A
JEE Main 2026 (Online) 21st January Evening Shift
27

Correct statements for an element with atomic number 9 are: Choose the correct answer from the options given below:

  1. A and B Only
  2. A, C and D Only
  3. A and C Only
  4. C and D Only
JEE Main 2025 (Online) 8th April Evening Shift
28

The energy of an electron in the first Bohr orbit of the H-atom is -13.6 eV. The magnitude of energy value of an electron in the first excited state of Be3+ is eV (nearest integer value).

JEE Main 2025 (Online) 8th April Evening Shift
29

[figure] Which of the following statements are correct, if the threshold frequency of caesium is 5.16 1014 Hz? Choose the correct answer from the options given below:

  1. B, C and D Only
  2. A, C, D and E Only
  3. A, B, D and E Only
  4. A, D and E Only
JEE Main 2025 (Online) 7th April Morning Shift
30

The extra stability of half-filled subshell is due to : Identify the correct statements :

  1. B, D and E only
  2. A, B, D and E only
  3. B, C and D only
  4. A, B and D only
JEE Main 2025 (Online) 7th April Evening Shift