Bond Character of Fluorine

[MelanieAu1G]

What would be the bond character of fluorine involved in a sigma bond, for example in CH3F? I attended a review session this past weekend in which the TA told me that the sigma bond characteristics between the carbon and fluorine atoms would be (C 2sp3,F 2p), respectively. His explanation for not having a hybridized orbital on the F atom was that it (and the other halogens) already has 7 valence electrons and therefore has room to accept another electron in the p-orbital, so hybridization is unnecessary. However, I was still a bit confused as to why this is, especially considering that F still has electrons occupying the 2s- orbital, so I brought the question up in discussion to which my TA gave me another answer. He rationed that the sigma bond characteristics between C and F would be (C 2sp3,F 2sp3) because the F atom still has electrons occupying the s- and p- orbitals, even though it has 7 valence electrons and one remaining space within the p-orbital to fill that sub-shell. If anyone has any input, please share! Thank you!

[Alexandra Watts 3L]

The second answer is right (2sp3), because you still use hybridization to form the sp hybrid orbital. The s orbital and two of the p orbitals are already full with Flourine's valence electrons, while the one electron left in the third p orbital has room for one more electron (the one bond that Flourine has in that molecule)