the elements beryllium and boron are exceptions to the octet rule. what is the correct lewis electron dot…

Answer:

The second structure (the one with B in the center and three F atoms bonded to it with single - bonds and each F having 3 lone pairs) is the correct Lewis electron - dot structure for BF₃.

Explanation:

Step1: Determine valence electrons

B has 3 valence electrons and each F has 7 valence electrons. Total valence electrons = 3+(3×7)=24.

Step2: Place central atom

B is the central atom as it is less electronegative than F.

Step3: Bonding and lone - pairs

B forms single bonds with 3 F atoms. Each F has 3 lone pairs to complete its octet (except B which is an exception to the octet rule and has 6 electrons around it in BF₃). The first structure is incorrect as it has an incorrect bonding pattern (F - F bonds are not present in BF₃). The second and third structures have the correct connectivity, but we need to ensure the correct number of electrons are accounted for. The correct structure has B in the center with single bonds to 3 F atoms and each F having 3 lone pairs.