halides!!!!

[KathChem82]

Please help! I'd greatly appreciate a most immediate response as I need this asap.
The Phosphorus trihalides (PX3) show the following variation in the bond angle X-P-X: PF3, 96.3 degrees; PCl3, 100.3 degrees; PBr3, 101.0 degrees' PI3, 102.0 degrees. The trend is generally attributed to the change in electronegativity of the halogen.

1. Assuming that all electron domains exhibit the same repulsion, what value of the X-P-X angle is predicted by the VSEPR model?

2. What is the general trend in the X-P-X angle as the electronegativity increases?

3. Using the VSEPR model, explain the observed trend in the X-P-X angle as the electronegativity of X changes.

4. Based on your answer on question 2, predict the structure of PBrCl4.