Is PO4(3-) polar or non-polar?

Why or why not?

Thanks!

Look up the electronegativity of P and O. I think I remember that O is about 3.5 and P is about 2.1; therefore, each P-O bond is somewhat polar. Thus, the ion will be polar unless the Lewis structure (electron dot structure) is symmetrical. Do you know how to determine that?

1 P = 5 electrons

4 O = 4 x 6e each = 24 electrons

-charge = 3e

Total = 5 + 24 + 3 = 32 electrons.

We have 5 atoms and the octet rules means we need 40 electrons (5 x 8 = 40); thus, 32 electrons must do the job of 40.

P is the central atom. Place 4 O around it at 90 degrees; i.e., top, right side, bottom, left side. 32 electrons will allow each atom to have eight. Its hard to draw on the computer but here goes.

   :O:

:O:P:O:

   :O:

Now place .. above and below each O and that will use 32 electrons. This means we have a tetrahedral structure. That is symmetrical; therefore, the PO4-3 is not polar.