kelly c asked in 社會與文化語言 · 1 decade ago

About chemistry

How do i know when to use double bonds or single bonds when making the lewis dot structure?

For example, why does nitrogen only make three single bonds (lines) with flourine in NF3, leaving a lone pair, when it can just as easily make it with 2 single bonds and 1 double bond leaving no lone pairs?

Update:

what about O3?

1 Answer

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  • 1 decade ago
    Best Answer

    The key thing you have to remember is that 8 is the happy number. Everyone tries to have 8 electrons, and when they don't have it, they share with others to get 8. So for NF3, nitrogen has 5 electrons, flourine each have 7 electrons. In order for everyone to have 8, each flourine share 1 electron with nitrogen, and the nitrogen shares three electrons with the flourines

    another example is O2, each oxygen has 6 electrons, so when 2 oxygen each share 2 electrons with the other, they will have 8 electrons, so that makes a double bond

    i hope that help you a little!

    2009-06-16 05:20:30 補充:

    For O3, i think the electron shifts between the oxygen. i am not too sure, it's been a while since i've done any chemistry

    you can find out more at wikipedia, i think they explain more(http://en.wikipedia.org/wiki/Ozone)

    2009-06-16 05:21:00 補充:

    oh, i forgot to mention, when you share 1 electron, that makes a single bond; share 2 electrons is a double bond...etc.

    Source(s): , me, and wikipedia, me, and wikipedia
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