Octet rule

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Hanniel U 2B
Posts: 76
Joined: Fri Sep 28, 2018 12:16 am

Octet rule

Postby Hanniel U 2B » Wed Oct 31, 2018 12:19 pm

Can someone please explain the octet rule and why the first 4 atoms on the periodic table don't have it. Thanks !

Te Jung Yang 4K
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

Re: Octet rule

Postby Te Jung Yang 4K » Wed Oct 31, 2018 12:28 pm

The octet rule is basically a guideline for bonding which says that elements (with atomic number below 20) should have 4 bonding pairs of electrons (8 e- total - the noble gas configuration).

The first 4 elements do not follow this guideline as they do not need 8 e- to reach a noble gas configuration to feel stable, they can simply have 2 e- to reach the configuration of He.

But be wary, there are exceptions to this guideline that were discussed in class: expanded octet, B and Al, and radicals.

Hanniel U 2B
Posts: 76
Joined: Fri Sep 28, 2018 12:16 am

Re: Octet rule

Postby Hanniel U 2B » Wed Oct 31, 2018 12:30 pm

Te Jung Yang 1G wrote:The octet rule is basically a guideline for bonding which says that elements (with atomic number below 20) should have 4 bonding pairs of electrons (8 e- total - the noble gas configuration).

The first 4 elements do not follow this guideline as they do not need 8 e- to reach a noble gas configuration to feel stable, they can simply have 2 e- to reach the configuration of He.

But be wary, there are exceptions to this guideline that were discussed in class: expanded octet, B and Al, and radicals.

Thanks!


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