Boron achieves only a sextet, not an octet, in BF₃

Steps:

• Boron has 3 valence electrons and forms 3 single bonds with fluorine, sharing 2 electrons per bond.
• This gives boron 6 electrons in its valence shell (3 from itself + 3 from bonds).
• Noble gas configuration requires 8 electrons (octet rule) for stability, like neon.
• Boron's incomplete octet makes the bonding unusual.

Why B is correct:

• Boron ends with 6 valence electrons, violating the octet rule that atoms seek 8 electrons for noble gas stability.

Why the others are wrong:

• A: Non-metals routinely form covalent bonds, as in H₂O or CO₂.
• C: Covalent bonds are defined by shared electron pairs between atoms.
• D: Each fluorine gains 8 electrons, achieving neon's configuration.

Final answer: B