Question

what are the quantum numbers of the valence electron in potassium atom (z=19) in ground state?

Answer 1

first electronic config. of K =  1s² 2s² 2p⁶  3s² 3p⁶ 4s¹

sp the e⁻ in 4s is our valence electron

hence its quantum no.s →

n = 4

l = 0

m = 0

s =  +1 or -1