When a piece of sodium metal is placed in water, there is a violent reaction and a big explosion. Table salt, made of sodium chloride, also has sodium in it, but why doesn't it explode when added to water? The reason is that there are different types of sodium in the two compounds. In sodium metal, the sodium atoms are neutrally charged, without an electric charge. In sodium chloride, the sodium atoms are ionized, with one fewer electron that sodium metal. Sodium metal has one electron in its outermost energy level, and that causes it to be unstable, so that it reacts violently with water. The Sodium ion, on the other hand, has lost the electron, so that it does not react with water, because it is much more stable.