What are the octet exceptions?

[tonyhu]

And why?

[Andrew Liang 1I]

P, S , and Cl are the common exceptions to the octet rule. They can hold more than 8 valence electrons because atom in period 3 or higher have d-orbital in valence shell that allows them to hold additional electrons

[Jialun Chen 4F]

The first four elements, which are H, He, Li, and Be, are the exceptions to the octet rule.

[Matthew Tsai 2H]

Elements beyond the third row of the periodic table are able to hold extra valence electrons beyond the octet because they have an unfilled d-orbital.

[Nicholas_Gladkov_2J]

n = 3 energy levels, or elements after P, have access to an empty d-orbital. Because of this accessible d-orbital, the elements are exceptions to the octet rule. Elements in group 13 (column with B, Al, etc.) are also exceptions with 3 pairs of e-, rather than an octet.

[ZevMarx-Kahn3C]

n = 3 energy levels, or elements after P, have access to an empty d-orbital. Because of this accessible d-orbital, the elements are exceptions to the octet rule. Elements in group 13 (column with B, Al, etc.) are also exceptions with 3 pairs of e-, rather than an octet.

Why are these group 13 elements exceptions?

[Ayushi2011]

Generally d-block elements because the d-orbital can accommodate more valence electrons.

[Siddiq 1E]

Past the 2p level, atoms can contain more electrons.

[Megan_1F]

Elements in the 3p block can have an expanded octet.

[TheresaDsilva4A]

Based on the homework problems, an element that is commonly associated with an expanded octet (hypervalence) is the noble gas Xenon. Boron and Aluminum are two elements that often exist in compounds with an incomplete octet. Hope this helps!

[Jennifer Yang 3F]

Elements in group 13, like Boron, can have 3 pairs of e- instead of the octet.

[504939134]

Octet exceptions are the first 4 elements in the periodic table which are; H,He,Li, and Be, as they will never have a full octet. An exception to this octet guideline are all elements after Neon, so in the 3p block and on, these elements are allowed to have more than 8 electrons, they don’t have to follow the octet guideline.