lewis structures

[005199302]

What are the exceptions to the octet rule? Is Br one of them?

[ChathuriGunasekera1D]

Some of the exception are H, He, Li, Be because they don't have enough electrons to even make the octet. Sulfur, chlorine, silicon and phosphorus can all go beyond the octet, so they are also exceptions. There are some more for sure, but Br follows the octet rule (someone please correct me if I'm wrong).

[gwynlu1L]

From what I remember from lecture, Lavelle said atoms in the 3rd row have the potential to have an expanded octet because the electrons in the d orbitals can become available for bonding. In addition, molecules that have an odd number of electrons such as NO or NO2 may be exceptions to the rule as well since there is no way to draw a lewis structure that gives each atom 8 electrons.

[Nicklas_Wright_1A]

Nitrogen, Boron, and Beryllium are exceptions. They can have less than 8 valence electrons.