# Why are the electronic configuration numbers the way they are? 2,8,18,32 ...so on- how were they determined?

## Please right the answer for kids

Feb 15, 2018

Bohr's Model.

#### Explanation:

As Niels Bohr suggested that electrons will Fill up the shells according to the principal quantum number.

So, for K shell, the principal quantum number($n$) is 1.

So, maximum electrons which can fill the cells are $2 {n}^{2}$ = $2 {\left(1\right)}^{2}$ = $2$.

For L shell, maximum electrons = $2 {\left(2\right)}^{2}$ = $8$

For M shell, maximum electrons = $2 {\left(3\right)}^{2}$ = $18$

For N shell, maximum electrons = $2 {\left(4\right)}^{2}$ = $32$

And So On.

But this doesn't mean that electrons will fill up from K to L.

It depends upon Azimuthal Quantum Number and Aufbau Principle.

Hope this helps.