Br 2+

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204301116
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Joined: Fri Sep 26, 2014 2:02 pm

Br 2+

Postby 204301116 » Wed Dec 10, 2014 12:08 am

In one of the practice finals it says that Br 2+ is diamagnetic. Can someone please explain this to me? I thought it should be paramagnetic with 2 unpaired electrons.

Shreyesi Srivastava 2D
Posts: 11
Joined: Fri Sep 26, 2014 2:02 pm

Re: Br 2+

Postby Shreyesi Srivastava 2D » Wed Dec 10, 2014 12:15 am

Someone else had this issue and posted it here as well. If you do the molecular orbital diagram Br2 2+ is paramagnetic- it has unpaired electrons in the 3pi*x and 3pi*y. However, Br2 is diamagnetic as shown in this: http://chemwiki.ucdavis.edu/@api/deki/f ... revision=1

Is this a typo?

Sohaib Kazmi 4H
Posts: 10
Joined: Fri Sep 26, 2014 2:02 pm

Re: Br 2+

Postby Sohaib Kazmi 4H » Wed Dec 10, 2014 4:57 pm

Br has 7 valence electrons, so Br2 should have 14. Br2 2+, however, should have 2 less electrons.

Br2 2+ should be paramagnetic because when you remove the 2 electrons, the 3pi-x and 3pi-y will be unpaired, like Shreyesi said. I'm pretty sure it's a typo, you could check with Lavelle.

Nikolina Walas-3J
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Joined: Fri Sep 26, 2014 2:02 pm

Re: Br 2+

Postby Nikolina Walas-3J » Thu Dec 11, 2014 2:37 pm

how would you draw the MO diagram if there is a d shell filled?

Sohaib Kazmi 4H
Posts: 10
Joined: Fri Sep 26, 2014 2:02 pm

Re: Br 2+

Postby Sohaib Kazmi 4H » Thu Dec 11, 2014 4:48 pm

The d-orbital shouldn't matter because it doesn't affect the valence electron count, which is what determines bond order and magnetism in the MO diagram. That being said I'd be interested to see how the d-orbital affects MO diagrams as well.

Nikolina Walas-3J
Posts: 19
Joined: Fri Sep 26, 2014 2:02 pm

Re: Br 2+

Postby Nikolina Walas-3J » Sat Dec 13, 2014 5:11 pm

I actually don't think the D orbital would affect the MO diagram because its a lower energy level, so the valence would only be 4s and 4p

Nicole Ng IC
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Joined: Fri Sep 26, 2014 2:02 pm

Re: Br 2+

Postby Nicole Ng IC » Sat Dec 13, 2014 9:41 pm

I had the same problem.
When you remove the two electrons, one is from the pi*px and one from the pi*py, so those two orbitals would be unpaired. Hence the molecule would be paramagnetic. I don't think d orbitals are involved in any way.
I might have been a typo because the answer key generalized the pi*p orbitals and wrote (pi*p)2, which is actually pi*px1 and pi*py1

Chelsea Zeng 4E
Posts: 11
Joined: Fri Sep 26, 2014 2:02 pm

Re: Br 2+

Postby Chelsea Zeng 4E » Sat Dec 13, 2014 11:37 pm

So just double checking.... it is a typo right?


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