Step-by-step explanation:
Sodium sulfate
Na₂SO₄
The sulfate ion is SO₄²⁻
Sodium sulfite
Na₂SO₃
The sulfite ion is SO₃⁻
Sodium sulfide
Na₂S
The sulfide ion is S²⁻
Sodium phosphate
Na₂PO₄
Phosphate ion is PO₄²⁻
Sodium phosphite
Na₃PO₃
The phosphite is PO₃³⁻
Sodium phosphide
Na₃P
The phosphide ion is P³⁻