The chemical properties of metals are much harder to observe because they result from the way electrons are arranged in the atom. Metals have one, two, or three electrons in their outermost shell. Since metals lose electrons, they will react with water or other elements. A chemical reaction which results in the wearing away of the metal to change it into a metallic compound, is called corrosion . A rusting nail or tarnishing silver are examples of corrosion.
Nonmetals also have some observable physical properties.
The chemical properties of nonmetals result from the fact that they have five, six, or seven electrons in their outermost shell. Nonmetals have a tendency to gain electrons to fill up the outermost level. Generally, there is an energy change that occurs when a chemical reaction takes place. The baking of a cake or bread or heating the iron filing and sulfur to produce iron sulfide are examples of such a reaction. If heat is released it is a result of the chemical reaction, this energy change is called exothermic .