Transition metals, alloys and corrosion GapFill

 ConversionMetamorphicEssentialAlkaliMedialTransition metals, such as iron, are found in the central block of the periodic table. They are metals, but they have very different chemical and physical properties from the metals in Group 1. For example:

• they are  hardermore stablemore conductivemore reactivemore brittlemore fluid
• they change state at a higher temperature, so have higher melting points
• their strength is higher, so they are often used in construction
• they react less vigorously with oxygen,  baseshydrogenwatersulfuracidscarbon dioxide and halogens

They can often be used as  reagentscatalystsenzymesendothermsmagnetssolvents to speed up reactions. They can also form  negativearomaticcovalentelectroniccolouredreflective compounds, and have ions with different  sizeschargesshapesnumbers of protonsmagnetic propertiesenergy levels.

Over time, materials will react chemically to become damaged or corroded; chemically, this process is known as  chippingfatiguelosing HPcorrosionwear and teardestruction. In the specific case of iron, this process is called rusting. Rusting requires the iron to be exposed to  just waterother metalsheatnitrogenradiationair and water. To prevent this damage occurring, metals are often coated in another material, such as paint, or  a radioactive substancea more reactive metala less reactive metalgelstonea noble gas is attached to the metal's surface so that it reacts preferentially to the metal, a process known as sacrificial protection.

Two or more metals can be mixed together to create what is known as  glassa cocktailan alloyreinforcementa polymera mixer. An example is steel, which is iron with different amounts of  oxygencarboncopperzinchydrogenchlorine and other metals added. Because it is a mixture of metals, steel has distorted layers, and so is  shinierpalerstrongerdullersofterdarker than pure iron.