Half filled exception

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Adrienne B 1J
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Joined: Sat Feb 24, 2018 3:00 am

Half filled exception

Postby Adrienne B 1J » Sat May 05, 2018 6:47 pm


my TA mentioned a half filled exception today for electron configuration but I'm not quite sure what is meant by this.

Posts: 27
Joined: Fri Feb 02, 2018 3:00 am

Re: Half filled exception

Postby 004985802 » Sat May 05, 2018 7:04 pm

it may have been referring to the d block favoring being half or fully filled (meaning having d^5 or d^10) so if the atom has two electrons in the valence s orbital and 4 or 9 electrons in the d valence orbital, an electron will move from the s to the d orbital to have it half or fully filled

Emily 1E
Posts: 27
Joined: Fri Apr 06, 2018 11:03 am

Re: Half filled exception

Postby Emily 1E » Sun May 06, 2018 6:26 pm

Chromium is an example of the half filled exception. Instead of being Cr = [Ar] 4s^2 3d^4 as expected following the usual rules, it is 4s^1 3d^5. Because the 3d sub shell is more energetically stable if it has one electron in each of its 5 orbitals, that if it were to have only 4.

Ani Boyadjian 1A
Posts: 30
Joined: Fri Apr 06, 2018 11:02 am

Re: Half filled exception

Postby Ani Boyadjian 1A » Sun Jun 03, 2018 4:34 pm

This would occur in an atom with an electron configuration where its (n-1)d orbital contains 4 or 9 electrons. The atom will be more stable if it takes an electron from the (n)s^2 orbital making the (n-1)d orbital contain 5 electrons (half-full) or 10 electrons (full orbital) while (n)s orbital will contain 1 electron (ns^1).

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