Z>8, Z<8

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Jane Sin 3A
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Joined: Wed Sep 21, 2016 2:58 pm

Z>8, Z<8

Postby Jane Sin 3A » Mon Nov 07, 2016 9:54 pm

I know Z is nuclear charge, and I know the consequent shape of the molecular orbital diagram, but I am confused with how we calculate the value of Z. Am I right in saying that the Z value is found from the number of valence electrons from the p orbital? For example, O2 has 4+4 electrons in the p orbital, so it has 8 electrons, and thus counts as Z>8? And N2 has 3+3 electrons in the p orbital, and is thus 6 for Z and Z<8?

vsyacoubian2A
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Joined: Fri Jul 22, 2016 3:00 am

Re: Z>8, Z<8

Postby vsyacoubian2A » Mon Nov 07, 2016 10:09 pm

Z stands for atomic number. So it means that elements that have an atomic number less than 8 or greater than 8 have a certain molecular orbital structure.

Jane Sin 3A
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Joined: Wed Sep 21, 2016 2:58 pm

Re: Z>8, Z<8

Postby Jane Sin 3A » Mon Nov 07, 2016 10:41 pm

Then can you explain why NO+ has a molecular orbital diagram that corresponds to z<8?

Elan Karlin Dis3H
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Re: Z>8, Z<8

Postby Elan Karlin Dis3H » Tue Nov 08, 2016 12:03 am

It is because both these atoms have less than eight valence electrons

shannon_tseng_3L
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Joined: Wed Sep 21, 2016 2:56 pm

Re: Z>8, Z<8

Postby shannon_tseng_3L » Tue Nov 08, 2016 12:56 am

what would happen if one atom in a molecule has atomic number greater than 8 and the other has Z less than 8?

Jane Sin 3A
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Joined: Wed Sep 21, 2016 2:58 pm

Re: Z>8, Z<8

Postby Jane Sin 3A » Tue Nov 08, 2016 10:42 am

Okay so I found out from my discussion today that only HOMONUCLEAR problems (same atoms,e.g. O2) need the whole z>8 or z<8 thing. Heteronuclear (different atoms, e.g. NO) will always be a certain order, unconcerning z. So, for homonuclear problems, you just check the atomic number (z) to find out if z is greater than or less than 8. So, O2 has an atomic number of 8 (because O has an atomic number of 8). Basically, elements H through N are Z<8, and O to F are Z>8.

Jane Sin 3A
Posts: 28
Joined: Wed Sep 21, 2016 2:58 pm

Re: Z>8, Z<8

Postby Jane Sin 3A » Tue Nov 08, 2016 10:43 am

Heteronuclear problems like NO will always have a shape like Z<8.

Kristina Mercolino 3C
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Joined: Fri Jul 15, 2016 3:00 am

Re: Z>8, Z<8

Postby Kristina Mercolino 3C » Tue Nov 08, 2016 2:19 pm

Why does an atom with an atomic number >/= 8 have the 2pi and 2 sigma orbitals switch? What is the reason for this switch?

Alejandra_Vasquez_1B
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Joined: Wed Sep 21, 2016 2:56 pm

Re: Z>8, Z<8

Postby Alejandra_Vasquez_1B » Tue Nov 08, 2016 2:51 pm

As long as one atom in the compound is less than 8, then you will have to use the z<8 diagram. It doesn't matter if one atom is greater than 8, you still have to use the z<8 diagram because of the atom that is less than 8.


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