Answer:
Mg(s) + Sn²⁺(aq) ⇄ Mg²⁺(aq) + Sn(s)
Explanation:
Let's consider the following molecular equation.
Mg(s) + SnSO₄(aq) ⇄ MgSO₄(aq) + Sn(s)
The full ionic equation includes al the ions and the species that do not dissociate in water.
Mg(s) + Sn²⁺(aq) + SO₄²⁻(aq) ⇄ Mg²⁺(aq) + SO₄²⁻(aq) + Sn(s)
The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the species that do not dissociate in water.
Mg(s) + Sn²⁺(aq) ⇄ Mg²⁺(aq) + Sn(s)
The complete chemical reaction of aqueous Sodium sulfate and aqueous Barium nitrate is

The right side and the left side of the reaction have equal number of elements, therefore it is balanced.
A spring - also an electromagnet. Also know as a slinky!