Question

Which of the following molecules include a central atom that does not obey the octet rule?

1.) NO₂
2.) SF₆
3.) CS₂
4.) BF₃

Answer 1

BF₃ is the molecule that includes a central atom that does not obey the octet rule. The boron atom in BF₃ has only six electrons in its valence shell instead of eight.

Step-by-step explanation:

Among the given molecules, BF₃ is the molecule that includes a central atom that does not obey the octet rule. The boron atom in BF₃ has only six electrons in its valence shell instead of the usual eight. Although it is possible to draw a Lewis structure with a double bond between boron and fluorine, experimental evidence suggests that the actual structure has three single bonds and an electron-deficient boron.