Moderate

Consider one He⁺ ion in an excited state (n = 5). Which of the following observations will hold true as per Bohr's model?

Correct answer: D. The electronic separation from the center of the nucleus is more than 6Å

  • A. 10 emission spectral lines will be seen
  • B. The ionization energy needed is less than 2 eV
  • C. The longest emitted wavelength is less than 10/R (R = Rydberg's constant)
  • D. The electronic separation from the center of the nucleus is more than 6Å

Explanation

The radius of the orbit is calculated by r = a₀(n²/Z), where a₀ ≈ 0.529 Å. For a He⁺ ion (Z=2) in the n=5 state, the radius is r = 0.529 × (5²/2) = 6.61 Å. This value is greater than 6 Å. Option A can also be considered along with option D.

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