Why does steel rust?

Answer by  Sebastiaan (19)

Steel contains iron and iron has the chemical property to react naturally with oxidants since iron lacks 2 or 3 electrons (so it is positively charged). If steel comes in contact with water and oxygen a chemical reaction will take place (iron receives electrons from oxygen) and iron oxides are formed, this is rust.

Answer by  ScottHorn (232)

Steel is a mixture of iron and other elements. Steel rusts primarily because the iron it contains reacts with oxygen to for iron oxide, or rust.

Answer by  ChemDoc (154)

Iron (one component of "steel") is most stable as the +2 ion, not as the metal. Therefore, it loses two electrons and combines with oxygen to make iron oxide-- rust.