Octet Exceptions

[Donna Nguyen 2L]

Why are the elements H, He, Li, and Be exceptions to the octet rule?

[Zaynab Hashm 2I]

H and He only require 2 electrons for their highest energy shell to be full (they only have 1s that needs to be filled with only 2 electrons rather than 8).

Li and Be are metals that tend to lose electrons rather than gain them to get a positive charge, hence going back to the lower noble gas configuration which is He and that, as mentioned before, has only 2 electrons in the outermost (and only) shell.

[dtolentino1E]

their valence shells are 1s and 2s, which don't even have enough orbitals for eight electrons. these elements are stable with just 2 (H, He) or 4 (Li, Be)