Identify the ions present in the reactants. From BeCl_2(aq), you have \(\text{Be}^{2+}(aq)\) and \(2\text{Cl}^-(aq)\), and from NaOH(aq), you have \(\text{Na}^+(aq)\) and \(\text{OH}^-(aq)\) ions.
Write the full ionic equation by separating all strong electrolytes into their ions: \(\text{Be}^{2+}(aq) + 2\text{Cl}^-(aq) + 2\text{Na}^+(aq) + 2\text{OH}^-(aq) \rightarrow \text{Be(OH)}_2(s) + 2\text{Na}^+(aq) + 2\text{Cl}^-(aq)\).
Identify the spectator ions, which are ions that appear unchanged on both sides of the equation. Here, \(\text{Na}^+(aq)\) and \(\text{Cl}^-(aq)\) are spectator ions.
Remove the spectator ions from the full ionic equation to write the net ionic equation. This leaves you with \(\text{Be}^{2+}(aq) + 2\text{OH}^-(aq) \rightarrow \text{Be(OH)}_2(s)\).
Confirm that the net ionic equation shows the formation of the solid precipitate \(\text{Be(OH)}_2(s)\) from the aqueous ions, which represents the actual chemical change occurring in the reaction.