To determine the number of valence electrons that need to be accommodated in the Lewis structure for OF2, we need to consider the valence electron counts of each atom involved.

- Oxygen (O) belongs to Group 16 and has 6 valence electrons.

- Fluorine (F) belongs to Group 17 and has 7 valence electrons.

In OF2, there is one oxygen atom and two fluorine atoms. So, the total number of valence electrons that need to be accommodated in the Lewis structure is:

6 (from oxygen) + 2 x 7 (from two fluorine atoms) = 20 valence electrons.