Question

if k l m shell of an atom of completely filled with electron what would be .the total no of electron in atom.find it valency

Answer 1

when k l m shells are completely filled
electronic distribution = K L M
2 8 8
valency = 8- valence electron
= 0
valency is 0.

Answer 2

K L M

2 8 8 total electrons = 2+8+8 = 18

When in outermost shell if there is 5,6,7,8 then we find valency by 8 -5

Valency= 3

8-6 = 2

8-7= 1

According to your question valency will be 8-8 = 0.