Problem: How do you write the reaction of lead(II) nitrate (aq) with sodium iodide (aq) to form lead (II) iodide precipitate and sodium nitrate solution?

Before balancing the chemical reaction, let’s first write the chemical formula of the compounds involved in the reaction.

Reactants:

Lead (II) nitrate 

▪ Lead (II) → +2 charge → Pb⁺

▪ Nitrate ion → -1 charge → NO₃^- 

▪ Combine both ions, the charge of the ion goes to the subscript of the counterion

Lead (II) nitrate: Pb(NO₃)₂ (aq)