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 Subject: The noblegas brickbrain quest Category: Science > Physics Asked by: vendel-ga List Price: \$3.00 Posted: 12 Jul 2006 17:01 PDT Expires: 11 Aug 2006 17:01 PDT Question ID: 745777
 ```Argon have three electron rings 2,8,8 and has fullfilled its outer rings. Krypton have four rings; 2,8,18(??),8 How come Krypton have eighteen electrons in its third ring, while argon have eight, and still is a noble gas if its outer ring can be added further with electrons? How does the periodic system work according to the numbering of rings? as far as I know, a noble gas is an atom that has fullfilled its outer electron ring. Which is why I find this third-ring argon/krypton kinda frustrating :) Thank You```
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 Subject: Re: The noblegas brickbrain quest From: iang-ga on 13 Jul 2006 15:07 PDT
 ```Krypton is 2,8,8,18 not 2,8,18,8 Ian G.```
 Subject: Re: The noblegas brickbrain quest From: physci-ga on 13 Jul 2006 19:05 PDT
 ```If you examine a table of the electron configurations of the ground states of the elements you will see that this occurs repeatedly: #18 A 2,8,8 #19 K 2,8,8,1 Starts filling the N shell #20 Ca 2,8,8,2 #21 Se 2,8,9,2 Goes back and adds to the M shell #22 Ti 2,8,10,2 #36 Kr 2,8,18,8 #37 Rb 2,8,18,8,1 #38 Sr 2,8,18,8,2 #39 Y 2,8,18,9,2 The ground state is the lowest state and although it seems that both A and Kr could add additional electrons to their outer shell, the energy required to do this is large - the energy required to move an electron from the ground state to an excited state is large so that makes them inert gasses.```
 Subject: Re: The noblegas brickbrain quest From: iang-ga on 14 Jul 2006 00:49 PDT
 ```Sorry - I was wrong! Ian G.```
 Subject: Re: The noblegas brickbrain quest From: adhikarla-ga on 20 Jul 2006 06:25 PDT
 ```electrons in any atom are filled in accordance with the Aufbau("building up") principle. follow the article on this principle at : http://www.iun.edu/~cpanhd/C101webnotes/modern-atomic-theory/aufbau-principle.html Then try to follow this, Argon has 3 quantum states and a valency of 18 which gives it the following configuration: 1s2 (2) 2s2 2p6 (8) 3s2 3p6 (8) Krypton, on the other hand has 4 quantum states and a valency of 36 which imparts it the following configuration: 1s2 (2) 2s2 2p6 (8) 3s2 3p6 3d10 (18) 4s2 4p6 (8) Try looking up more articles on Aufbau principle and these things should be clear to you....bfn```
 Subject: Re: The noblegas brickbrain quest From: deepidm-ga on 31 Jul 2006 02:19 PDT
 ```elecrons set themselves according to the bohr-bury principle there are three rules to be followed first-the formula to calculate the number of electrns in a ring is 2(n^2),where n is the number of the ring, example-1 for first ring, 2 for second ring second-the last ring cannot have more than 8 electrons third-the second last ring cannot have more than 18 electrons. so, Krypton has 36 electrons the first shell has 2(1^2)=2 electrons the second shell has 2(2^2)=8 electrons the third has 2(3^2)=18 electrons the fourth is the last so it can hold just 8 electrons 2+8+18+8=36 so, krypton has 18 in the third shell```