Question

Which one of the following set of quantum numbers is not possible for electron in the ground state of an atom with atomic number 19?

• A. $ n=2,l=0,\text{ }m=0 $
• B. $ n=2,l=1,m=0 $
• C. $ n=3,l=1,m=-1 $
• D. $ n=3,l=2,\text{ }m=+2 $
• E. $ n=4,\text{ }l=0,\text{ }m=0 $

Answer 1

Answer: (D)

$ K(Z=19):\text{ 1}{{s}^{2}},\text{ }2{{s}^{2}}2{{p}^{6}},3{{s}^{2}}3{{p}^{6}},4{{s}^{1}} $ In the ground state the value of I can be either zero or one. Hence, the set (d) of quantum numbers i.e., $ (n=3,\text{ }Z=2,m=+2) $ cannot possible in the ground state.