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Offline chilli

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question about covalent bonds
« on: January 28, 2016, 06:04:22 PM »
hello all!
I was wondering why is it that a compound like N2F2 doesn't create a triple covalent bond, after all every N has a "spare" pair of electrons, why in certain compounds or molecules triple bonds will form and not in others and how to identify it?
thx in advance!

Offline AWK

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Re: question about covalent bonds
« Reply #1 on: January 28, 2016, 06:24:57 PM »
Draw Lewis structure of this compound
AWK

Offline chilli

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Re: question about covalent bonds
« Reply #2 on: January 28, 2016, 06:29:47 PM »
I did, that's why I asked, had 2 pairs of electrons for every N and wasn't sure where to place them, then found out its not a triple bond and wondered why

Offline mikasaur

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Re: question about covalent bonds
« Reply #3 on: January 28, 2016, 07:01:03 PM »
Where would the triple bond go? Between the nitrogens?

Nitrogen is a period 2 element and so must follow the octet rule. If there were a single bond, a triple bond, and a single lone electron for each nitrogen you'd be breaking the octet rule.
Or you could, you know, Google it.

Offline chilli

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Re: question about covalent bonds
« Reply #4 on: January 28, 2016, 07:11:23 PM »
I'm attaching a link I hope its ok:
www.youtube.com/watch?v=VTd0w8RGxVE
those electrons on top, why cant they join the other four in between N's and form a triple one? the octet will remain only with a triple bond, no?

Offline chilli

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Re: question about covalent bonds
« Reply #5 on: January 28, 2016, 07:24:40 PM »
Ohhhhh, I just figured out my mistake lol
had to see it big to get it haha, for some reason I calculated them as 2 electrons and not 4 (as if there was only 1 electron on each N) ty all for answers!
on that note, why there are no quadruple bonds?

Offline Burner

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Re: question about covalent bonds
« Reply #6 on: January 28, 2016, 08:01:50 PM »
https://en.wikipedia.org/wiki/Quadruple_bond

Quadruple bonds means that a total number of eight electrons are shared between the atoms... I think that not many atoms can hold such a huge number of electrons. (Just a noob explanation)
Year 1 science student in HKUST and a Chemistry geek.
If I make any mistakes in the forum, please don't hesitate to correct me as I want to learn.

Offline chilli

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Re: question about covalent bonds
« Reply #7 on: January 28, 2016, 08:30:30 PM »
ty for link! this is very interesting, wish I knew more and could fully understand it
what do u mean when u say that only few atoms can hold that number of electrons? what will happen to them?

Offline Burner

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Re: question about covalent bonds
« Reply #8 on: January 28, 2016, 09:26:19 PM »
what do u mean when u say that only few atoms can hold that number of electrons? what will happen to them?

I think it reason should be related to orbitals or something like that though I know nothing about orbital.

If I had to explain, I would say that smaller atoms has fewer positively-charged protons to attract electrons so they can't carry a too negative charge(formal charge?) when they gain too much electrons from a quadruple bond. Also, in transition metals usually there are 1 or 2 electrons in the outermost electron shell only and there may be 'spaces' for holding more electrons.

Please kindly correct me if I have make any mistakes or give a better explanation.
Year 1 science student in HKUST and a Chemistry geek.
If I make any mistakes in the forum, please don't hesitate to correct me as I want to learn.

Offline mikasaur

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Re: question about covalent bonds
« Reply #9 on: January 28, 2016, 10:31:43 PM »
One more student chiming in. (This is an example of the blind leading the blind leading the blind... hooray students!). I believe you're on the right track thinking about smaller atoms but maybe don't quite have the reasoning right.

You'll eventually learn about hybridization and molecular orbital theory. Small atoms like N only have electrons in their s and p orbitals. When you learn about orbital shapes and hybridization you'll see how electrons in s and p orbitals make σ bonds and π bonds and what single, double, and triple bonds really are.

Bigger elements have electrons in their d and f orbitals! The d orbital is especially cool and it can make δ bonds.

Molecular orbital theory helps explain bond orders and other things (like why dinitrogen is a triple bond and why dioxygen is paramagnetic!) and if you go to the big elements involved in compounds like dimolybdenum you'll see sextuple bonds!

So yes it has to do with the "size" of an atom and the number of electrons it can hold. But really the big difference between N and Mo is that Mo already has electrons in a bunch of different orbitals -- many of which are very close in energy and can form interesting bonds.
Or you could, you know, Google it.

Offline chilli

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Re: question about covalent bonds
« Reply #10 on: January 29, 2016, 12:34:09 PM »
wow, very interesting, very complex
so, (I'm just a beginner so excuse my questions) is the most basic thing in chemistry is actually electrical relationships?

Offline mikasaur

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Re: question about covalent bonds
« Reply #11 on: January 29, 2016, 12:45:13 PM »
Hmm, well a lot of undergraduate courses in chemistry actually start with physics and the nature of atoms and subatomic particles. That's "basic" in that it's the basis for which interactions take place between atoms and compounds. So yeah you could argue it's the most "basic" thing in chemistry, I guess.
Or you could, you know, Google it.

Offline Corribus

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Re: question about covalent bonds
« Reply #12 on: January 29, 2016, 02:45:14 PM »
wow, very interesting, very complex
so, (I'm just a beginner so excuse my questions) is the most basic thing in chemistry is actually electrical relationships?
Chemistry is, essentially, the study and manipulation of the movement of electrons.
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 chilli

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Re: question about covalent bonds
« Reply #13 on: January 30, 2016, 04:05:05 PM »
that is so cool, ty all for answers it was very interesting!

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