Octet Rule  [ENDORSED]

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Octet Rule

Postby Maldonado3K » Sun Oct 29, 2017 11:29 pm

Can someone please explain the octet rule more in depth and give examples of when it should be applied? Thanks.

Nora Sharp 1C
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Joined: Sat Jul 22, 2017 3:00 am

Re: Octet Rule  [ENDORSED]

Postby Nora Sharp 1C » Mon Oct 30, 2017 12:21 am

I think the octet rule is usually used when drawing lewis structures. This is the idea that bonding atoms generally end up with their electrons in the electron configuration of a noble gas; as in, they all have 8 electrons in their valence shells. The octet rule does have exceptions, however. It does not apply to hydrogen, which only needs 2 electrons in its valence shell to reach noble gas configuration. The octet rule may not also apply to certain elements, like phosphorous and sulfur, both of which can have 12 bonded electrons when bonded to 6 other atoms (SF6 is an example), and boron, which can show up in configurations with less than 8 valence electrons like BF3.

However, other atoms follow the octet rule in most circumstances. Take H20 as an example when drawing a lewis structure.

Start by adding up the electrons:
Hx2: 2 electrons
O: 6 valence electrons
Total: 8 electrons

Each hydrogen needs 2 electrons to be "happy" (one single bond) and oxygen must fulfill the octet rule. Since both hydrogens only "want" one single bond with the oxygen, we're left with oxygen bonded to two hydrogens, along with four valence electrons in a space of their own. This fulfills the octet rule without giving the hydrogen atoms too many electrons. Here's what it looks like:

https://d2gne97vdumgn3.cloudfront.net/a ... GxYo83Mx8d

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