Exceptions

[Natalie Vu 1I]

How do the exceptions H, He, Li, and Be work?

[Joanna Zhao 1J]

H, He, Li, and Be are exceptions to the Octet guideline because those elements are inclined to reach He's noble gas configuration, which only has 2 (valence) electrons (filling n = 1). So, by definition, those elements do not follow the Octet Rule/Guideline that other s and p block elements follow of wanting to have 8 valence electrons.

[Molly Smith 1J]

Those 4 elements will never create an octet of electrons and are therefore the exception because most other elements tend to want to get an octet to be most stable. However, since those 4 elements naturally have very few electrons, to get to 8 would actually make the atom less stable rather than more stable because so many electrons would be added to its ground state. I hope this helps!

[Cecilia Lei 3K]

They are exceptions to the octet rule because they have too less electrons in the outer shell, making them impossible to fulfill the 8 electrons in their outer shell. Also, they don’t have the orbitals enough to hold 8 electrons.

[Jordan Kaplan 2E]

The exceptions for H, He, Li, and Be are because they only fill up the s orbitals. Unlike other elements, which would have a p orbital with 6e- plus the 2e- from the s orbital (8 total for the octet rule) these 4 elements specifically will only have 2e- in their outer most shell.

[Aneesha_Nema_3C]

H, He, Li, and Be are exceptions to the octet rule because they are all inclined to only fill up the s orbitals. They would never be able to have 8 electrons in their outer shells, and therefore are exempt from the octet rule for valence electrons.

[Sarah3C]

Do the exceptions to the rule mean they never follow the octet rule or just that they do not HAVE to?