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Structure of Atom

JEE Main 2025 (Online) 4th April Evening ShiftMCQEasy📈 Topic in 8% papers+4−1
Ques. 1JEE Main 2025, 4 April (Evening Shift)

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

Answer

(2) 12 and 5

Solution

Cr (Z = 24): 1s2 2s2 2p6 3s2 3p6 3d5 4s1 (half-filled 3d is extra stable)

l = 1 (p electrons): 2p6 + 3p6 = 12

l = 2 (d electrons): 3d5 = 5

Answer: (2)

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Ques. 2JEE Main 2025, 3 April (Morning Shift)

Which of the following postulate of Bohr's model of hydrogen atom is not in agreement with quantum mechanical model of an atom?

  1. The electron in a H atom's stationary state moves in a circle around the nucleus.
  2. An atom can take only certain distinct energies E1, E2, E3, etc. These allowed states of constant energy are called the stationary states of atom.
  3. An atom in a stationary state does not emit electromagnetic radiation as long as it stays in the same state.
  4. When an electron makes a transition from a higher energy stationary state to a lower energy stationary state, then it emits a photon of light.
Ques. 3JEE Main 2025, 3 April (Evening Shift)

For electrons in '2s' and '2p' orbitals, the orbital angular momentum values, respectively are:

  1. 0 and 6 h2
  2. 0 and 2 h2
  3. 2 h2 and 0
  4. h2 and 2 h2
Ques. 4JEE Main 2025, 2 April (Morning Shift)

According to Bohr's model of hydrogen atom, which of the following statement is incorrect?

  1. Radius of 4th orbit is four times larger than that of 2nd orbit
  2. Radius of 8th orbit is four times larger than that of 4th orbit
  3. Radius of 6th orbit is three times larger than that of 4th orbit
  4. Radius of 3rd orbit is nine times larger than that of 1st orbit
Ques. 5JEE Main 2025, 2 April (Evening Shift)

Which of the following statements are true? Choose the correct answer from the options given below:

  1. (A) and (B) only
  2. (B) and (D) only
  3. (C) and (D) only
  4. (A), (B) and (C) only
Ques. 6JEE Main 2025, 29 January (Morning Shift)

If a0 is denoted as the Bohr radius of hydrogen atom, then what is the de Broglie wavelength (λ) of the electron present in the second orbit of hydrogen atom? [n : any integer]

  1. 8 a0n
  2. 2a0n
  3. na04
  4. 4 a0n
Ques. 7JEE Main 2025, 29 January (Evening Shift)

For hydrogen like species, which of the following graphs provides the most appropriate representation of E vs Z plot for a constant n? [E : Energy of the stationary state, Z : atomic number, n = principal quantum number]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 8JEE Main 2025, 29 January (Evening Shift)

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

  1. Statement I is false but Statement II is true
  2. Both Statement I and Statement II are true
  3. Both Statement I and Statement II are false
  4. Statement I is true but Statement II is false
Ques. 9JEE Main 2025, 28 January (Morning Shift)

In a multielectron atom, which of the following orbitals described by three quantum numbers will have same energy in absence of electric and magnetic fields? Choose the correct answer from the options given below:

  1. B and C Only
  2. C and D Only
  3. A and B Only
  4. D and E Only
Ques. 10JEE Main 2025, 28 January (Evening Shift)

Which of the following is/are not correct with respect to energy of atomic orbitals of hydrogen atom? Choose the correct answer from the options given below :

  1. (A) and (B) only
  2. (A) and (C) only
  3. (B) and (D) only
  4. (C) and (D) only
Ques. 11JEE Main 2025, 24 January (Evening Shift)

For hydrogen atom, the orbital/s with lowest energy is/are : Choose the correct answer from the options given below :

  1. A only
  2. B only
  3. B, C and D only
  4. A and E only

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