Following Octet Rule? How do you know when it is impossible??

Question

Draw Lewis structures for the following compounds/ions. In which of the compounds/ions listed is the octet rule (or the duet rule for hydrogen) impossible to satisfy for all atoms in the formula? Choose "Impossible" or "Possible" in regards to satisfying the octet rule (not in regards to if the compound can exist or not)



NF₃

 CCl₃

 SeO₂^2-

 SF₄

 AsF₅

 SO₃

Answer 1

NF3 possible

CCl3 impossible

SeO2 2- impossible

SF4 impossible

AsF5 impossible

SO3 impossible