Question

We all know that potassium, the 19th element on the periodic table has the electronic configuration of 2.8.8.1. However, why not 2.8.9?. I would like to know why potassium is not 2.8.9.

Answer 1

Because an element can not handle more than 8 electrons in its each shell .( Except K shell which can hold only 2 electrons )
Hope it helps ........