AP Chemistrymediummcq1 pt
Why is boron trifluoride (BF₃) an exception to the octet rule?
A.Boron completes only six valence electrons
B.Boron holds twelve electrons
C.Fluorine gives boron electrons
D.Boron has no valence electrons
Explanation
Core Concept
Boron has three valence electrons and forms three B–F bonds, totaling six electrons around boron. Elements of periods 2–3 below carbon often fall short of an octet when doing so avoids formal charge.
Correct Answer
ABoron completes only six valence electrons
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