When a magnesium bromide solution is mixed with a lead(II) nitrate solution, a precipitate forms. Determine the balanced molecular equation, the complete ionic equation, and the net ionic equation.

MgBr₂(aq) + Pb(NO₃)₂(aq) → PbBr₂(s) + Mg(NO₃)₂(aq)

The electrolyte in the solution produces ions.

The equation of a chemical reaction can be expressed in the equation of the ions

For strong electrolytes (the ionization rate = 1) is written in the form of separate ions, while the weak electrolyte (degree of ionization <1) is still written as an un-ionized molecule

In the ion equation, there is a spectator ion that is the ion which does not change (does not react) because it is present before and after the reaction

When these ions are removed, the ionic equation is called the net ionic equation

For gases and solids including water (H₂O) can be written as an ionized molecule

A molecular equation is a chemical equation expressed as a molecule

So only the dissolved compound is ionized ((expressed in symbol aq)

Reaction

MgBr₂(aq) + Pb(NO₃)₂(aq) → PbBr₂(s) + Mg(NO₃)₂(aq)

Mg²⁺(aq)+2Br⁻(aq) + Pb²⁺(aq)+2NO₃⁻(aq)⇒PbBr₂(s) + Mg²⁺(aq)+2NO₃⁻(aq)

spectator ions : Mg²⁺(aq) and 2NO₃⁻(aq)

2Br⁻(aq) + Pb²⁺(aq)⇒PbBr₂(s)