The shape of the bf3 molecule is best described as

t-shaped
see-saw
tetrahedral
trigonal planar

The shape of the BF3 molecule is best described as trigonal planar.

Explanation:

The Lewis Structure for BF3 is like this:

 _            _

| F |        | F |

   \          /

        B

         |

      | F |

       ---

It forms three angles of 120° each. The bonds are in the same planar that's why it is trigonal planar and they are exactly the same.

Boron and Fluorine have 3 covalent bonds, produced by electronic promotion that enables the 2py and 2pz orbitals, leaving an electron to pair in the 2px. So boron will have 3 possible electrons to pair in 2s1, 2px and 2py, remember that electronic configuration for B is 1s2, 2s2, 2p1

By hybridization between the orbitals 2s2 and 2p1, the electrons of F, can joined to make the covalent bond. The new B configuration is 1s2, 2s1, 2px1, 2py1 (these last three, hybrid orbitals)