chloebird
Badges: 13
Rep:
?
#1
Report Thread starter 1 year ago
#1
So I’ve just come across a question about covalent bonding which relies on the fact that arsenic has 5 outer shell electrons (with the electron configuration 4s2 4p3) which makes sense to me if I write out its entire electron configuration. However, this suggests that there are 18 electrons in the third electron shell (3s2 3p6 3d10) instead of the GSCE standard which was that there are 2 electrons in the first shell and 8 in all the others. So is this true?? Do we have to use the fact that the third shell can take 18 electrons now? Because if I write out the GCSE electron configuration I get 2.8.8.8.7 and if arsenic has 7 outer shell electrons the Bonding doesn’t work. Help 😭😭
0
reply
Izzayyyy
Badges: 13
Rep:
?
#2
Report 1 year ago
#2
Forget about the gcse configuration... just use the one with 18 in the outer shell because there are all the sub shells now that we don’t do at gcse.
1
reply
username3718068
Badges: 11
Rep:
?
#3
Report 1 year ago
#3
(Original post by chloebird)
So I’ve just come across a question about covalent bonding which relies on the fact that arsenic has 5 outer shell electrons (with the electron configuration 4s2 4p3) which makes sense to me if I write out its entire electron configuration. However, this suggests that there are 18 electrons in the third electron shell (3s2 3p6 3d10) instead of the GSCE standard which was that there are 2 electrons in the first shell and 8 in all the others. So is this true?? Do we have to use the fact that the third shell can take 18 electrons now? Because if I write out the GCSE electron configuration I get 2.8.8.8.7 and if arsenic has 7 outer shell electrons the Bonding doesn’t work. Help 😭😭
GCSE electron configuration is false (just forget about it and pretend it didn't exist in the first place) . The "2 electrons in first shell, and 8 electrons in others" is not true.

The maximum number of electrons in any main energy level is calculated as : 2n^2 (where n is the nth main energy level)
So yes, in the 3rd main energy level there are 2 x 3^2 = 18 maximum electrons. This equation is completely consistent with the current quantum model of the atom.
1
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • University of Hertfordshire
    All Subjects Undergraduate
    Sat, 22 Feb '20
  • Ravensbourne University London
    Undergraduate Open Day Undergraduate
    Sat, 22 Feb '20
  • Sheffield Hallam University
    Get into Teaching in South Yorkshire Undergraduate
    Wed, 26 Feb '20

People at uni: do initiations (like heavy drinking) put you off joining sports societies?

Yes (370)
67.27%
No (180)
32.73%

Watched Threads

View All
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise