octet exceptions

[Katherine Chhen 3I]

How would we know if a molecule is an exception to the octet rule?

[Jarrett Peyrefitte 2K]

Molecules that have exceptions to the octet rule are molecules with an odd number of electrons (ex. NO) , molecules in which an atom or more than one atom have more than 8 electrons (ex. SF6) , and molecules in which an atom or more than one atom have less than 8 electrons (ex. BCl3) .

[Serena Siddiq 3D]

You know if it is an octet exception if you are drawing the Lewis structure and you are not matching up with the amount of electrons it should have because the bonds you make lower the amount of lone pairs to be counted on the separate atom. If this happens, as long as it is the central atom is in period 3 and higher, it can exceed the octet rule because it has access to the d orbital, which can always hold more electrons, even if that specific atom only goes up to a 3s or 3p in its own configuration. So, you can add an extra lone pair or so to the central atom in order to reach the calculated electron count of the molecule to get an accurate structure. Hope that helps!

[melinak1]

Molecules that have exceptions to the octet rule are molecules with an odd number of electrons (ex. NO) , molecules in which an atom or more than one atom have more than 8 electrons (ex. SF6) , and molecules in which an atom or more than one atom have less than 8 electrons (ex. BCl3) .

thank you!!!

[Jorge Ramirez_4H]

How about elements in the third row?

[Kallista McCarty 1C]

How about elements in the third row?

Third row elements can have an expanded octet (up to 18 electrons, but they typically have 10-12)