Question

Why the electronic configration of pottasium is 2,8,8,1 if maximum electrons in m shell is 18

Answer 1

Electronic configuration of potassium is 2 8 8 1.

Yes, you are right that M-shell can contain maximum 18 electrons but in this element M-shell is having 8 electrons only and 1 electron is in N-shell, which can be explained by octet rule which states that outer most shell can contain only 8 electrons, so if one N electron is also present in M-shell and configuration is 2, 8, 9 so octet rule will be violated. Shell M can contain 18 electrons only when 1 electron is there for N-shell also.