Question

An atom has 2 electrons in K shell, 8 electrons in L shell and 8 electrons in M shell. The number of s electrons present in the element is :

• A. 10
• B. 7
• C. 6
• D. 4

Answer 1

The correct option is C 6

K L M
2 8 8

Thus, atomic number of the element will be 18.

And electronic configuration of the element can be given as:
$1s^{2}2s^{2}2p^{6}3s^{2}3p^6$

Thus, total number of s electron is 6.