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Q: The noblegas brickbrain quest ( No Answer,   5 Comments )
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
There is no answer at this time.

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 :

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.
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
so, krypton has 18 in the third shell

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