Question #39125

1 Answer
Jun 9, 2017

Because M shell has the capacity for 8 electrons. Secondly, 18
is used for all the sub shells in the M shell.

Explanation:

M shell has the capacity to store 8 electrons.
We have divided 18 in three sub shells of the shell M ,e.g.,
3s = 2
3p = 6
3d = 10
Now add them,
2+6+10 = 18
Electronic configuration of Ca =
1s^2, 2s^2,2p^6, 3s^2,3p^6, 4s^2, where;
K = 2
L = 8
M = 8
N = 2

You can take 18 as a whole but, if you'll take the M shell it contains 8 electrons, if we'll also count its sub shell electro configuration then it will be greater than 8.