thanks for the help.
so total valence electron would be 5+24+3 = 32 for PO4- ?
8 electonrs are used to from 4 bonds between P and O. It leaves 24 electrons..
Then three oxgens would equally share 24 electrons, having 6 electrons per one oxgen atom.
Then Na would attach to 3 oxgens. Is there any special notation that I have to put on to indicate the bond between oxgen and Na is ionic?