Can someone explain this hybrid orbital chem problem?

Question

"What atomic or hybrid orbitals make up the sigma bond between As and F in hexafluoroarsenate ion, AsF6- ?


sp3d2 orbital on As + 2p orbital on F



What are the approximate F-As-F bond angles ? (list all possible) ... 90 1800

Feedback:

The Lewis structure for AsF6- is: ... There are 6 σ bonds and 0 lone pairs around As giving rise to sp3d2 hybridization on As.

The As-F σ bond is therefore made up of one sp3d2 orbital on As and one 2p orbital on F.

The sp3d2 hybridization on As results in approximate F-As-F bond angles of 90 1800. "

I understand the sp3d2 on As. Why is it 2p on F? How are you supposed to know what it's supposed to be on F? The stupid feedback section didn't even give an explanation, it explained the sp3d2 and gave nothing to explain why it's 2p for F.

Answer 1

Look at the electron configuration of Fluorine:
1s^2 2s^2 2p^5
Thus the outer shell is for principle number 2 and you need 1 e in the 2p orbitals to have a complete outer shell.

The angles are explained by the hybridization: it is octahedral thus the angles F-As-F of the bonds on plane are 90, of one bond one the plane and one on the axis again 90, and of the 2 As-F bonds on the vertical axis 180 deg.