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Topic: Question on magnetic behaviour of atoms, ions, compound.  (Read 4904 times)

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Offline junbumkim

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Question on magnetic behaviour of atoms, ions, compound.
« on: April 11, 2007, 06:05:36 AM »
So i read that any compund with odd number of valence electron is paramagentic.

is that because odd number of valence electron means no paired electron in the outermost orbit?
So if there there is ANY paired electron in the outer orbit, the atom or compound is dismagentic?

I was looking at two molecules
[Co(NH3)6]3+ and [CoF6] 3-
the first compound has valence electrons of [9+6(5+3)] -3 = 54 -> dimagentic

the latter one has valence electrons of 9+42 +3 = 54 -> dismagentic...
but the answer says the latter one is paramagentic...

Can someone expound on this please??

Offline AWK

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Re: Question on magnetic behaviour of atoms, ions, compound.
« Reply #1 on: April 11, 2007, 06:35:27 AM »
Number of electrons is insufficient property to resolve problem of diamagnetism or paramagnetism. Read something on the crystal field theory or the ligand field theory. Start from your textbook or wikipedia
AWK

Offline Borek

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Re: Question on magnetic behaviour of atoms, ions, compound.
« Reply #2 on: April 11, 2007, 07:47:14 AM »
So i read that any compund with odd number of valence electron is paramagentic.

It doesn't mean that compunds with even number of valence electrons are not!

Every even number larger then 3 is not a prime. Does it mean that every odd number larger than 3 is a prime?
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Offline Ψ×Ψ

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Re: Question on magnetic behaviour of atoms, ions, compound.
« Reply #3 on: April 11, 2007, 10:23:23 AM »
Paramagnetism also depends on the spin states of the electrons.  Diatomic oxygen has an even number of electrons, but is paramagnetic because of the way the orbitals are arranged.  (There's a nifty little demonstration out there that you might Google.)

Offline junbumkim

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Re: Question on magnetic behaviour of atoms, ions, compound.
« Reply #4 on: April 11, 2007, 10:07:04 PM »
ok, which of the following compounds would you expect to be weakly to be drawn into a magnetic filed?

 H2, NaCl, NO, NO2, BF3, PCl5, SO2


Offline Borek

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Re: Question on magnetic behaviour of atoms, ions, compound.
« Reply #5 on: April 12, 2007, 02:50:33 AM »
Please read forum rules.
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Offline junbumkim

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Re: Question on magnetic behaviour of atoms, ions, compound.
« Reply #6 on: April 12, 2007, 07:04:29 AM »
Well, this isn't my homework...
I am studying for PCAT, and it's one of the problems. The book says that para / dimagnetism can depend on the number of valence electrons....

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