Question

According to the formula 2n² there should be 18electrons but we put only 8 electrons. Why??

Answer 1

It is the rule (a rule for determing electronic configuration) which is to be followed for the filling of the no. of electrons where n is the shell number

K shell - 2(1^2)= 2 electrons

L shell - 2(2^2)=8 electrons

M shell - 2(3^2)= 18 electrons

N shell - 2(4^2)=32 electons

There is one more rule which you need to follow that the last shell or the valence shell can at max occupy 8 elctrons not more than 8…

For instance if the valence shell is N shell then it can not have 32 electrons rather it can have 8 have elctrons..