Metal can refer to: Heavy metal music
Metals are shiny, solid, and conductive elements. A common example is iron. They contrast with the nonmetals. They are generally found on the left side of the periodic table. Most elements in the periodic table are classified as metals. In astronomy and cosmology, the term "metals" includes any elements other than hydrogen or helium. This is termed metallicity.
Properties of Metals
Most metals have the following properties:
- They have high melting points and boiling points
- They are good conductors of heat and electricity
- They tend to be quite dense
- When cut, the newly exposed surface is shiny and this dulls over time with oxidation
- They are ductile (meaning they can be drawn out to form wires)
- They are malleable (meaning they can be deformed into other shapes, e.g. pressed to form sheets)
Not all metals have all these properties, but share a number of them. Some metals such as titanium and aluminum are strong and have a low density, while others are soft and very dense, like lead. mercury is a liquid at room temperature and gallium has a melting point of 30°C and will melt in your hand.
Most metals are reducing agents. The reactivity of metals varies drastically. The alkali metals and alkaline earth metals have to be stored in oil because they react with water and air vigorously. Gold and platinum on the other hand are extremely unreactive.
Metals tend to have a crystalline structure. They consist of ions arranged in a regular, periodic fashion, surrounded by delocalized electrons. These delocalized electrons can move freely throughout the metal, meaning metals can easily conduct an electrical current or heat. The interaction between the sea of delocalized electrons and the positive ions is called a metallic bond.