Here's how to break down the formula Na₂SO₄ to determine the number of ions:

* Na₂SO₄: This formula represents sodium sulfate.

* Na₂: The subscript "2" indicates there are two sodium ions (Na⁺).

* SO₄²⁻: The sulfate ion (SO₄²⁻) has a charge of -2, meaning it's a single ion.

Therefore, Na₂SO₄ contains two Na⁺ ions and one SO₄²⁻ ion.