Question

If n = 6, the correct sequence for filling of electrons will be, ……

(a) ns → (n – 2) f → (n – 1) d → np 

(b) ns → (n – 1) d → (n – 2) f → np 

(c) ns → (n – 2) f → np → (n – 1) d

(d) none of these are correct

Answer 1

(a) ns \(\rightarrow\) (n – 2) f \(\rightarrow\) (n – l) d \(\rightarrow\) np

n = 6 

According Aufbau principle, 

6s → 4f → 5d → 6p 

ns → (n – 1) f → (n – 2) d → np.