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)

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.