Question

which compound is an exception to the octet rule?
o h₂o
o hcl
o ccl₄
o bf₃

Explanation:

The octet rule states that atoms tend to gain, lose, or share electrons to have eight electrons in their outer - most shell. $H_2O$, $HCl$, and $CCl_4$ follow the octet rule. In $BF_3$, boron has only 6 electrons in its outer - most shell after forming bonds with three fluorine atoms, making it an exception to the octet rule.

Answer:

D. $BF_3$