Hard MCQ +4 / -1 PYQ · JEE Mains 2020

Consider the hypothetical situation where the azimuthal quantum number, $l$, takes values 0, 1, 2, ....., n + 1, where n is the principal quantum number. Then, the element with atomic number :

  1. A 13 has a half-filled valence subshell Correct answer
  2. B 9 is the first alkali metal
  3. C 8 is the first noble gas
  4. D 6 has a 2p-valence subshell

Solution

Under hypothetical situation, the value of l is greater than n which varies from 0 to n + 1. <br><br>For n = 1, l = 0, 1, 2 <br><br>n = 2, l = 0, 1, 2, 3 <br><br>Elements follow the following electronic configuration <br><br>1s 1p 1d 2s 2p 2d 2f <br><br>Atomic number (Z) = 9 <br>1s<sup>2</sup> 1p<sup>6</sup> 1d<sup>1</sup> <br><br>Atomic number = 6 <br>1s<sup>2</sup> 1p<sup>4</sup> <br><br>Atomic number 8 <br>1s<sup>2</sup> 1p<sup>6</sup> <br><br>Atomic number 13 <br>1s<sup>2</sup> 1p<sup>6</sup> 1d<sup>5</sup> (half filled)

About this question

Subject: Chemistry · Chapter: Atomic Structure · Topic: Bohr's Model

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