Metal

Metals are chemical elements that lose electrons to form positive ions. They also form metallic bonds when they combine with other metal atoms and metals and form ionic bonds when they combined with nonmetal atoms. The periodic table contains four kinds of metals: alkali metals, alkaline earth metals, transition metals, and post-transition metals. Metals can usually be oxidized easily. Metals are good electrical and heat conductors. They are malleable, ductile, and usually solid at room temperature. On the periodic table they can be located to the left of, but not touching, the heavy, stair-step line.

Periodic Table
Alkali metals: Alkali metals are found in group 1 on the periodic table. They are very reactive and have one electron in its outer shell. They are malleable, ductile, and are good conductors of both heat and electricity. They are softer than the other metals and they will explode if exposed to water. They are silvery in color and form ionic bonds with nonmetals.

Alkaline Earth Metals: Alkaline earth metals are found in group 2 of the periodic table. Because they have an oxidation number of +2 they are very reactive. They are hard, dense, and have high melting points. In their pure form they have a silvery or white appearance, but they change colors when they oxidize.

Transition Metals: The 38 elements that make up the transition metals are like a bridge between both sides of the periodic table. They are ductile, malleable, and conduct electricity and heat. Their valence electrons are found in more than one shell, which is why they have more than one oxidation number. Three of the elements in the transition metals Iron, Cobalt, and Nickel have been known to produce a magnetic field. 

Post-Transition Metals: The post-transition metals are metallic elements that are located to the right of the transition metals. The melting and boiling points are usually lower than the transition metals, and they are softer. Post-transition metals usually have a higher electronegativity. 

Types of Metals
Base metal: A base metal usually refers to a metal that oxidizes or corrodes easily. It also refers to metals that reacts with hydrochloric acid (HCl) which forms hydrogen. Some common base metals are iron, nickel, lead and zinc. In mining base metals refers to the non-ferrous metals not including precious metals. For example copper, aluminium, lead, nickel, tin and zinc. 

Ferrous metal: Ferrous metals contain iron. They are all magnetic and corrode easily. The most common is steel which includes stainless steel. Ferrous metals refer to ions that have iron(II) or Fe+2. If a iron's oxidation number is 2+ than it is a ferrous metal.

Precious metal: A precious metal is usually less reactive than most metals. They are soft, ductile, and have high melting points. Precious metals are used in art, jewelry, and currency. They are more expensive than other kinds of metals because they are considered more valuable. Examples of precious metals are gold, silver, and platinum. 

Alloys: An alloy is a combination of two or more elements and the main element is a metal. The most pure metals are too soft, brittle or chemically reactive so they can not be used easily. By combining different metals forming alloys it modifies the properties and produces usable materials. Alloys help make the elements less brittle, harder, and resistant to corrosion. Some alloys are steel which is the combination of iron and carbon, brass, which is the combination of copper and zinc, and bronze which is the combination of copper and tin. Alloys are used in special designs such as jet engines and can contain more than ten elements. 

Properties
Chemical: Metals can usually be oxidized easily. They can react with an acid in a single displacement reaction and the result would be hydrogen gas. Sodium and calcium can react with water to make a base. 

Ca(s) + 2H2O(l) --> Ca(OH)2(aq) + H2(g)

They usually have 1-3 electrons in their outer most energy level. They lose electrons easily and are good reducing agents. They also have a lower electronegativity compared to non-metals. 

Physical: Metals are good electrical and heat conductors. They are malleable, ductile, and usually solid at room temperature. Metals have a crystal structure in which each atom is surrounded by eight to twelve other atoms. Most metals have high densities compared to the nonmetals. But some have a low density like lithium which is the least dense solid. Osmium is the most dense element. The metals of groups 1 and 2 are often referred to as the light metals because they are not very dense. A metal's high density is caused by the tightly packed crystals of the metallic structure. Atoms in a metal are able to slide across one another when they are under stress. This makes it so the crystals can deform without shattering. Metals are good conductors because in metallic bonds the outer electrons of the metal atoms contain nearly free electrons. 

Metal or Nonmetal
Scientist use the electrolysis test to determine if an element is a metal or nonmetal. It involves placing the element in an acid and running an electrical current through the solution. If the element is a metal, then the atoms of the element will move towards the negative pole. If it is a nonmetal than the atoms will move towards the positive charge meaning that the element is negative. One of the main differences between metals and nonmetals is that atoms of nonmetals will try to fill their valence shells by sharing or transferring electrons. The characteristics of metals decrease with the increase in valence electrons. While nonmetals are the opposite, with the increase of valence electrons their characteristics increase. Some elements show characteristics of both metals and non-metals. Because they show a hybrid behavior they are sometimes referred to as metalloids or semiconductors. These elements include boron, silicon, germanium, arsenic, antimony, tellurium, and astatine. 

Extraction and Uses
Extraction: Metals are usually extracted from the earth by mining the ores that contain the metal. Ores are natural rocks that contain metal compounds in a large amount. The method for extracting a metal from its ore depends on how stable the ore is. Very reactive metals are extracted from the ore using electricity. Very reactive metals, such as aluminum, form stable oxides. A lot of energy is needed to reduce these metals to extract them from the ore. For higher reactive metals electrolysis is used. Less reactive metals are extracted from the ore by reduction with carbon. Less nonreactive metals, such as iron, form less stable oxides. Not as much energy is needed to extract the metal. The metals are extracted by a reaction with carbon or carbon monoxide. Gold is nonreactive and is found as a pure metal and not as a compound, this means that it doesn't need to be chemically separated. But chemical reactions are sometimes needed to remove other elements that contaminate the metal. 

Uses: Metals are used in buildings, bridge construction, vehicles, many appliances, tools, pipes, and railroad tracks because of its strength. The two most common metals are iron and aluminum. They are also the most abundant metals in the earth's crust. Because metals are good conductors they are important for carrying an electric current over a large distance with little energy loss. Power grids rely on metal cables to help distribute electricity over large spaces. Copper is used in wires because of its good conducting. Some metals are radioactive. For example, uranium and plutonium are used in nuclear power plants to produce energy through nuclear fission.