Na+4 doesn't exist because sodium can only give away one electron because that's all it has.
But maybe you are trying to say...
Na3PO4---> 3Na^+ + PO4^-3
what test would you form to verify the presence of the Na+4 and the Po4,3-ion in plant food
2 answers
You would need the chemical formula for plant food to see what it produces as products.