Final answer:
Sodium is highly reactive and reacts violently with water, while gold is very unreactive and does not react with water.
Step-by-step explanation:
The reactivity of sodium and gold can be compared by looking at their reactions with water. Sodium is a highly reactive metal and reacts violently with water, producing hydrogen gas and sodium hydroxide. Gold, on the other hand, is a very unreactive metal and does not react with water. This is due to the difference in their electron configurations and the stability of their electron shells.