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Topic: Bonding  (Read 2302 times)

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Offline aniond

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Bonding
« on: February 08, 2014, 08:49:12 PM »
I thought I understood bonding and lone pairs, now however I'm puzzled about a few things.

Let's take an oxygen atom for example. These are my assumptions, please tell me where I'm going wrong.

1) It has 6 valence electrons, or 3 lone pairs, by itself.
2) If it encounters two hydrogen atoms, it will form a full shell with 8 valence electrons, and become stable. Eg: H-O-H
3) The reason for this is because each hydrogen atom is donating an electron to fill its shell to a stable state.

Now my question is, what would happen hypothetically if 6 protons interacted with the oxygen atom. Since it has 6 valence electrons, why could these valence electrons not bond with 6 different protons (6H+) to form H6O? Since the protons would not be donating any electrons, the oxygen atom would remain at 6 valence electrons no? And this being unstable, two neutral hydrogen atoms could then bond to share their electrons to create a full valence shell to make H8O?

I realize this isn't possible, but why is it that an atom is limited to 4 bonds or less, if for example it interacts with a cation that isn't donating any electrons to give it a full shell?

Offline Corribus

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Re: Bonding
« Reply #1 on: February 09, 2014, 10:44:59 AM »
1) It has 6 valence electrons, or 3 lone pairs, by itself.
Not really. In the lone atom, there are six valence electrons. Two would go into filling the 2s orbital, and the other 4 would be distributed among the four 2p orbitals. Because of Pauli Exclusion Principle, two of these remain unpaired. (E.g., one filled 2p orbital and two half-filled 2 orbitals.)

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2) If it encounters two hydrogen atoms, it will form a full shell with 8 valence electrons, and become stable. Eg: H-O-H

OK, although at this point (see #3), atomic valence doesn't really have a well-defined meaning.

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3) The reason for this is because each hydrogen atom is donating an electron to fill its shell to a stable state.
You just have to be careful with your language. Hydrogen's valence electron is not donated to oxygen. It remains shared between oxygen and hydrogen.

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Now my question is, what would happen hypothetically if 6 protons interacted with the oxygen atom. Since it has 6 valence electrons, why could these valence electrons not bond with 6 different protons (6H+) to form H6O? Since the protons would not be donating any electrons, the oxygen atom would remain at 6 valence electrons no? And this being unstable, two neutral hydrogen atoms could then bond to share their electrons to create a full valence shell to make H8O?
Because to do this you'd have to promote some of oxygen's valence electrons up into higher atomic orbitals, which would take a fair bit of energy. Thermodynamics wins the day.

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I realize this isn't possible, but why is it that an atom is limited to 4 bonds or less, if for example it interacts with a cation that isn't donating any electrons to give it a full shell?

It's not - plenty of atoms have valencies higher than four. Sulfur hexafluoride, for example, has a sulfur atom with six bonds.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline aniond

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Re: Bonding
« Reply #2 on: February 10, 2014, 02:13:04 AM »
Thanks for explaining that Corribus. I feel like I need to study a bit more about the orbitals to get a more intuitive understanding.

Offline acvkrs

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Re: Bonding
« Reply #3 on: February 26, 2014, 12:42:25 PM »
the geometrical structure of orbitals doesn,t support those many bondings

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