Question

Correct set of four quantum numbers for the valence (outermost) electron of rubidium (Z = 37) is

(a)  5, 0,0, + 1/2

(b)  5,1,0, +1/2

(c)  5,1,1, + 1/2

(d)  6,0,0, +1/2

Answer 1

Correct option (a)  5, 0,0, + 1/2

Explanation:

Rb₃₇ = 2(2,6)(2,6,10)(2,6)(1)

= 1s²,2s²,2p⁶,3s², 3s²,3p⁶,4s²,3d¹⁰,4p⁶,5s¹

Valence electron is 5s¹