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Structure of Atom appeared 38 times across 3 years — 4.4% of Chemistry. This question is from Bohr Model for Hydrogen-like Species.

Year 2026 2025 2024 Total
Questions 14 15 9 38

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]

Solution & Explanation

Related Formula
Eₙ = -13.6 (Z²)/(n²) eV
Core Logic

For a constant principal quantum number n, the energy E is directly proportional to -Z². This represents a quadratic relation where the curve is a downward-opening parabola starting from the origin in the negative energy region.

Pattern Recognition

Since energy values are inherently negative for bound states, as Z increases, E becomes rapidly more negative following a parabolic curve.

Chapter Mix

Class 11 Chemistry: Structure of Atom

Reference Study Guides

More Structure of Atom Previous-Year Questions — Page 7

Q jee_main_2024_29_january_evening Hydrogen Spectral Series
Match List I with List II:
List I (Spectral Series for Hydrogen)List II (Spectral Region/Higher Energy State)
A. LymanI. Infrared region
B. BalmerII. UV region
C. PaschenIII. Infrared region
D. PfundIV. Visible region
Choose the correct answer from the options given below :
  • A. A-II, B-III, C-I, D-IV
  • B. A-I, B-III, C-II, D-IV
  • C. A-II, B-IV, C-III, D-I
  • D. A-I, B-II, C-III, D-IV

Solution

Related Formula
(1)/(λ) = RH ( (1)/(n₁²) - (1)/(n₂²) )
Core Logic

Analyzing electromagnetic spectrum regions for each hydrogen electronic decay series:

  • Lyman Series (n₁=1) emits photons in the high-energy Ultraviolet (UV) region (II).
  • Balmer Series (n₁=2) falls cleanly into the Visible region spectrum (IV).
  • Paschen Series (n₁=3) transitions sit inside the standard Near-Infrared region (III).
  • Pfund Series (n₁=5) shifts sit even deeper in the Infrared region zone (I).
Step 1: Resolution

Thus, compiling match mappings yields configuration: A-II, B-IV, C-III, D-I.

Pattern Recognition

Lyman is always UV; Balmer is visible; all subsequent higher level series (n₁ ≥ 3) belong strictly to infrared segments.

Chapter Mix

Class 11 Chemistry: Atomic Structure

Q jee_main_2024_27_jan_morning Quantum Numbers and Electron Capacity
The number of electrons present in all the completely filled subshells having n=4 and s=+(1)/(2) is . (Where n= principal quantum number and s= spin quantum number)
Numerical Answer. Answer: 16 to 16

Solution

Step 1: Identify all available subshells within the n=4 energy shell

For principal quantum level n=4, the allowed values of azimuthal quantum numbers (l) are:

  • 4s (l=0) arrow 1 orbital arrow 2 electrons capacity
  • 4p (l=1) arrow 3 orbitals arrow 6 electrons capacity
  • 4d (l=2) arrow 5 orbitals arrow 10 electrons capacity
  • 4f (l=3) arrow 7 orbitals arrow 14 electrons capacity
Step 2: Filter capacity using spin values

Every single spatial orbital holds exactly 2 electrons maximum; one with spin s=+(1)/(2) and one with spin s=-(1)/(2). Total number of orbitals across n=4 is:

1 + 3 + 5 + 7 = 16 orbitals

Thus, the total count of electrons featuring spin value s=+(1)/(2) across these completely filled configurations is exactly 16.

Pattern Recognition

Total orbitals in shell n is n². Since each orbital contributes exactly 1 electron with s=+(1)/(2), capacity is simply n² = 4² = 16.

Chapter Mix

Class 11 Chemistry: Structure of Atom

Q65 jee_main_2024_27_jan_morning Electronic Configuration and Magnetic Moment
Which of the following electronic configuration would be associated with the highest magnetic moment?
  • A. [Ar] 3d⁷
  • B. [Ar] 3d⁸
  • C. [Ar] 3d³
  • D. [Ar] 3d⁶

Solution

Related Formula

Spin-only magnetic moment formula:

μ = √(n(n+2)) BM

where n is the number of unpaired electrons.

Step 1: Audit configurations and count unpaired electrons

ConfigurationUnpaired e^- (n)Magnetic Moment (BM)
[Ar] 3d⁷3√(15)
[Ar] 3d⁸2√(8)
[Ar] 3d³3√(15)
[Ar] 3d⁶4√(24)

Step 2: Conclusion

Since [Ar] 3d⁶ contains the maximal count of 4 unpaired electrons, it yields the highest spin-only magnetic moment value.

Pattern Recognition

Maximal unpaired configuration in high-spin 3dⁿ series yields the highest μ. Check n systematically.

Chapter Mix

Class 11 Chemistry: Structure of Atom Class 12 Chemistry: d-and f-Block Elements

Q66 jee_main_2024_29_jan_morning Quantum Numbers
The correct set of four quantum numbers for the valence electron of rubidium atom (Z = 37) is:
  • A. 5, 0, 0, +(1)/(2)
  • B. 5, 0, 1, +(1)/(2)
  • C. 5, 1, 0, +(1)/(2)
  • D. 5, 1, 1, +(1)/(2)

Solution

Core Logic

Rubidium (Rb) has the atomic number Z = 37.

The noble gas core preceding it is Krypton (Kr, Z = 36). The electronic configuration is:

Rb arrow [Kr] 5s¹

Thus, the valence electron resides in the 5s orbital.

Step 1: Assigning Quantum Numbers

For a 5s electron:

  • Principal quantum number, n = 5 (from the shell number).
  • Azimuthal quantum number, l = 0 (for an s-orbital).
  • Magnetic quantum number, m = 0 (since m ranges from -l to +l, and l=0).
  • Spin quantum number, s = +(1)/(2) or -(1)/(2).
  • The correct set matching this is 5, 0, 0, +(1)/(2).

Chapter Mix

Class 11 Chemistry: Structure of Atom

Q90 jee_main_2024_30_january_evening Atomic Spectra
Number of spectral lines obtained in He^+ spectra, when an electron makes transition from fifth excited state to first excited state will be
Numerical Answer. Answer: 10 to 10

Solution

Related Formula
Number of spectral lines = (Δ n (Δ n + 1))/(2)

where Δ n = n₂ - n₁

Core Logic

Identify the principal quantum numbers (n) for the given states:

  • Fifth excited state means n₂ = 5 + 1 = 6.
  • First excited state means n₁ = 1 + 1 = 2.
  • Calculate the difference:

Δ n = n₂ - n₁ = 6 - 2 = 4
Step 1: Calculate Total Spectral Lines

Substitute Δ n = 4 into the formula:

Maximum number of spectral lines = (4(4 + 1))/(2) = (4 × 5)/(2)

= 10

Chapter Mix

Class 11 Chemistry: Structure of Atom

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