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Structure of Atom · Question 22

JEE Main 2026 (Online) 23rd January Evening ShiftMCQMedium📈 Topic in 10% papers+4−1
1

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

Answer

(2) A and C Only

Solution

A. 2412Mg: protons = 12, neutrons = 24 − 12 = 12. Incorrect.

B. = c = 3 1084.5 1015 = 6.7 10-8 m. Correct.

C. E 1 E1E2 = 2 1 = 300900 = 13 E1 : E2 = 1 : 3. Incorrect.

D. Energy of one photon = hc = 6.626 10-34 3 1082000 10-12 = 9.939 10-17 J

Number of photons = 19.939 10-17 = 1.006 1016. Correct.

Incorrect statements: A and C.

Answer: (2)

JEE Main 2026 (Online) 23rd January Evening Shift

Keep practising — Structure of Atom

2

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
3

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
4

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
5

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
6

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
7

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
8

[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
9

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
10

Which one of the following about an electron occupying the 1s orbital in a hydrogen atom is incorrect? (Bohr's radius is represented by a0)

  1. The probability density of finding the electron is maximum at the nucleus
  2. The total energy of the electron is maximum when it is at a distance a0 from the nucleus
  3. The electron can be found at a distance 2a0 from the nucleus
  4. The 1s orbital is spherically symmetrical
JEE Main 2025 (Online) 4th April Morning Shift
11

Consider the ground state of chromium atom (Z = 24). How many electrons are with Azimuthal quantum number l = 1 and l = 2 respectively ?

  1. 16 and 5
  2. 12 and 5
  3. 12 and 4
  4. 16 and 4
JEE Main 2025 (Online) 4th April Evening Shift

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