A salt, or sodium-chloride, molecule is made up of one sodium atom and one chlorine atom. It's formula is Na-Cl. Sodium is an extremely explosive metal that can ever react to water. Chlorine is a poisonous gas that was used in warfare in World War I. Could you imagine that these two highly reactive chemicals are sitting on your dinner table right now. Weather it is used in cooking or to melt snow on you driveway, salt is very useful and also very very surprising.