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Structure of Atom · Question 31

JEE Main 2025 (Online) 4th April Morning ShiftMCQEasy📈 Topic in 6% papers+4−1
1

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

Answer

(2) The total energy of the electron is maximum when it is at a distance a0 from the nucleus

Solution

(A) For the 1s orbital, 2 is maximum at the nucleus and decreases with distance. Correct.

(B) The energy of an electron in an orbital is fixed: E1 = -13.6 eV (or -2.18 10-18 J) for the 1s electron of H, whatever its distance from the nucleus. Only the radial probability is maximum at a0 (52.9 pm). Incorrect.

(C) The 1s orbital has no node, so 2 0 at any finite distance; the electron can be found at 2a0. Correct.

(D) As per NCERT, s orbitals are spherically symmetric. Correct.

The incorrect statement is (B).

Answer: (2)

JEE Main 2025 (Online) 4th April Morning Shift

Keep practising — Structure of Atom

2

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
3

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.
JEE Main 2025 (Online) 3rd April Morning Shift
4

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
JEE Main 2025 (Online) 3rd April Evening Shift
5

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
JEE Main 2025 (Online) 2nd April Morning Shift
6

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
JEE Main 2025 (Online) 2nd April Evening Shift
7

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
JEE Main 2025 (Online) 29th January Morning Shift
8

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
JEE Main 2025 (Online) 28th January Morning Shift
9

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
JEE Main 2025 (Online) 28th January Evening Shift

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