octet rule exceptions?

[Erica Li 1C]

I'm confused, are all the atoms outside of the period 2 ones able to have an expanded octet?

[Courtney McHargue 1I]

Lavelle said that elements in the third period or below are able to hold more than 8 valence electrons, typically sulfur, silicon, phosphorus and chlorine are the main ones known to have this ability.

[Emilee Hosking 1D]

Wait so periods 1 and 2 can both have more electrons than an octet? If so, are there any in the first 2 periods that can only reach an octet?

[Tuong Nguyen 2I]

Yes elements within the 3rd period/row can have more electrons than the octet rule allows. Also, the first four elements (Hydrogen, Helium, Lithium and Beryllium) and elements in column 14 can have incomplete octets (less that 8 electrons).

[LeannaPhan14BDis1D]

Is there a way to figure out which ones are allowed to contradict the octet rule or is it all of the ones from 3 and down.??

[MadisonB]

As a general rule, things become more complicated in terms of an expanded octet 3rd row and down, and the first few elements are stable with only two electrons. I found a more cut and dry rule for octet rule exceptions at this link: https://saylordotorg.github.io/text_gen ... -rule.html

their explanation is as follows: "However, there are three general exceptions to the octet rule: (1) molecules, such as NO, with an odd number of electrons; (2) molecules in which one or more atoms possess more than eight electrons, such as SF 6; and (3) molecules such as BCl 3, in which one or more atoms possess less than eight electrons."