At sports events around the world, we can see a small number of athletes fiercely competing on the field. They get tired, dirty, and sometimes hurt as they try to win the game. Surrounding them are thousands of spectators watching and cheering. Would the game be different without the spectators? Yes, it definitely would. They provide encouragement to the team and generate enthusiasm. The spectators are not really playing the game. We can write a molecular equation for the formation of silver chloride precipitate:.
The corresponding ionic equation is:. If you look carefully at the ionic equation, you will notice that the sodium ion and the nitrate ion appear unchanged on both sides of the equation. They can be eliminated from the reaction.
A spectator ion is an ion that does not take part in the chemical reaction and is found in solution both before and after the reaction. In the above reaction, the sodium ion and the nitrate ion are both spectator ions. The equation can now be written without the spectator ions. The net ionic equation is the chemical equation that shows only those elements, compounds, and ions that are directly involved in the chemical reaction.
A chemical equation written without the spectator ions is called a net ionic equation. A net ionic equation includes only those ions or compounds that undergo chemical change.
Spectator Ions Let's take a closer look at the reaction between sodium chloride and silver nitrate: Since both of the reactants are soluble in water, before a reaction occurs, sodium, chloride, silver, and nitrate ions are in solution. While spectator ions remain unchanged in solution and don't take part in the chemical reaction, they serve as a means of delivery for the materials required for the reaction.
To get silver chloride, the sodium ion delivers the chlorine ion while the nitrate ion delivers the silver ion into the reaction. Spectator ions bring in the participants for the chemical reaction but then don't take part themselves. Bert Markgraf is a freelance writer with a strong science and engineering background. Online he has written extensively on science-related topics in math, physics, chemistry and biology and has been published on sites such as Digital Landing and Reference.
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