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: (A) 6 has a 2

Question

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:

(A) 6 has a 2p-valence subshell
(B) 9 is the first alkali metal
(C) 8 is the first noble gas
(D) 13 has a half-filled valence subshell

Prashant Kotian · Accepted Answer

Correct answer: C. For n = 1 value of  = 0, 1, 2 For n = 2 value of  = 0, 1, 2, 3 So, according to n + l rule the filling order of subshells will be: 1s 1p 2s 1d 2p 3s 2d 3p 4s …….. (1) 1st noble gas will have configuration 1s2 1p6 so atomic number will be 8. (2) 1st alkali metal will have electronic configuration  1s1  (Z = 1) (3) Electronic configuration of C (Z = 6)  1s2 1p4 (4) Z = 13, Electronic configuration = 1s2 1p6 2s2 1d3 So it will not have half-filled electronic configuration. | JEE MAIN-2020 | DATE : 03-09-2020 (SHIFT-2) | PAPER-2 | OFFICIAL PAPER | CHEMISTRY PAGE # 5

💡 Solution & Explanation

Practice 22,000+ questions like this