Question

If an element has 3 electrons in total,how will you distribute it among the shells:

• A. 2 electrons in L shell and 1 electron in K shell
• B. All three electrons in L shell itself
• C. All three electrons in K shell itself
• D. 2 electrons in K shell and 1 electron in L shell

Answer 1

The correct option is D

2 electrons in K shell and 1 electron in L shell

K shell is the 1^st orbit having the lowest energy and filling of the electrons is from lowest energy to highest energy i.e the electrons are first filled in the K shell and then remaining electrons are filled in L shell.

Since according to 2 $\times$ $n^2$ formulae, the K shell can accommodate only 2 electrons and the remaining electrons are filled in L shell.