Start free

Chemistry · Structure of Atom

JEE Main 2026 — 4 April, Morning Shift — Question 50

Which of the following is correct set of 4 quantum number of 19th 19{ }^{\text {th }} electron in Chromium (Atomic number =24=24 ) in accordance with Aufbau principle?

  1. Option A:

    n=3,ℓ=2, m=+2, s=+12\mathrm{n}=3, \ell=2, \mathrm{~m}=+2, \mathrm{~s}=+\frac{1}{2}

  2. Option B:

    n=3,ℓ=2, m=−2, s=+12\mathrm{n}=3, \ell=2, \mathrm{~m}=-2, \mathrm{~s}=+\frac{1}{2}

  3. Option C:

    n=4,ℓ=1,m=0,s=+12n=4, \ell=1, m=0, s=+\frac{1}{2}

  4. Option D:

    n=4,ℓ=0, m=0, s=+12\mathrm{n}=4, \ell=0, \mathrm{~m}=0, \mathrm{~s}=+\frac{1}{2}

    Correct

Answer: D

Step-by-step solution

Cr⁡1s22s22p63s23p64s13d5\operatorname{Cr} 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1} 3 d^{5} ⇒19th e−\Rightarrow \quad 19^{\text {th }} \mathrm{e}^{-}belongs to 4s subshell n=4;ℓ=0;m=0;ms=+12\mathrm{n}=4 ; \ell=0 ; \mathrm{m}=0 ; \mathrm{m}_{\mathrm{s}}=+\frac{1}{2} or −12-\frac{1}{2}

Answer key and solution verified before publishing.

Practise Structure of Atom

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Solve a similar one free
Exam
JEE Main 2026
Paper
4 April, Morning Shift
Subject
Chemistry
Chapter
Structure of Atom
Topic
Electronic Configuration: Rules, Aufbau Principle and Exceptions

More Structure of Atom questions from this paper

Which of the following is correct set of 4 quantum number of 19 th… | JEE Main 2026 PYQ with Solution · DhiX AI