Login

can u tell me the electronic configuration of potassium as atomic mass 19. why this element have electric configuration 2,8,8,1 as we know that M shell contain 18 electrons. So why here it contains only 8 electrons.

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.

  • 6
View Full Answer

 hi chitrashee...

you are absolutely right about the M shell rule...but there is one more rule that the outer shell can contain a maximum of 8 electrons...so if you put 2,8,9 then this rule will be violated which isn't possible...shell M can contain 18 electrons only if there are at least 1 electron for the N shell..cz this wont violate the rule also.... 

  • 0

Nice answer Riya...... have my thumbs up for you........

Remember : The valence shell should always contain only 8 electrons and this is the Octet rule, no matter how many electons the shell can hold. So, the last shell cannot have 9 electrons in it. 

Hope this helps u.........

  • -3
What are you looking for?