Asked in Premeth Test 18 — Alkyl Halides, Aldehydes and Ketones, Atomic Structure (20 March 2025) 2025Moderate

If the principal quantum no. is 3 then the values of azimuthal quantum no. are

Correct answer: B. 0, 1, 2

  • A. 1, 2
  • B. 0, 1, 2
  • C. 1, 2, 3
  • D. -1, 0, 1

Explanation

The principal quantum number (n) determines the energy level of an electron in an atom. The azimuthal quantum number (l), which describes the shape of the orbital, can take integer values from 0 to n-1. Therefore, if n is 3, the possible values of l are 0, 1, and 2, corresponding to the s, p, and d orbitals, respectively.Option A (1, 2) is incorrect because it omits the value 0, which is required. Option C (1, 2, 3) is incorrect because it includes 3, which is not possible since l must be less than n. Option D (-1, 0, 1) is incorrect because azimuthal quantum numbers cannot be negative.

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About Quantum Numbers

Quantum numbers describe an electron's energy level, subshell, orbital orientation and spin. You examine the principal, azimuthal, magnetic and spin quantum numbers, their allowed values, orbital capacity and how they determine electronic configurations and distinguish electrons within an atom.

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