The four quantum numbers for the electron in the outermost orbital of potassium (atomic number 19) are:

Quantum Numbers of Potassium Valence Electron | JEE Main PYQ | Structure of Atom

Q. The four quantum numbers for the electron in the outermost orbital of potassium (atomic number 19) are:

(A) n = 3, l = 0, m = 1, s = +1/2

(B) n = 4, l = 0, m = 0, s = +1/2

(C) n = 2, l = 0, m = 0, s = +1/2

(D) n = 4, l = 2, m = −1, s = +1/2

Correct Answer: (B)

Explanation

Electronic configuration of potassium (Z = 19):

1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

The outermost electron lies in 4s orbital.

Therefore: n = 4, l = 0, m = 0, s = +1/2

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