The metals are the chemical elements able to drive the electricity and the hot , which exhibit a characteristic brightness and which, with the exception of mercury, are solid at normal temperature.
The concept is used to name pure elements or to alloys with metallic characteristics . Among the differences with nonmetals, it can be mentioned that metals have low ionization energy and low electronegativity.
Metals are tenacious (can receive forces abrupt without breaking), ductile (it is possible to mold them into wires or wires), malleable (they become sheets when compressed) and have a good mechanical resistance (Resist tensile, flexion, torsion and compression stress without deforming).
There are metals that appear in the form of native elements (the copper , he gold , the silver ), while others can be obtained from oxides, sulphides, carbonates or phosphates. Metals are often widely used in industry, as they offer great stability and have ample protection against corrosion.
The benefits of metals are known by the man since prehistory Initially, those that were easy to find in their purest form were used although, little by little, metals that were obtained from the use of furnaces began to be added.
The use of copper ore with tin allowed to create the alloy known as bronze , which gave rise to a new historical era (Bronze Age ).
Today you can distinguish between different types of metals, such as precious metals (which are in their natural state without the need to combine them with others to form compounds) and heavy metals (which exhibit a high density and have a certain toxicity).
Steel is a carbon alloy (of which it can contain between 0.04% and 2.25%) and iron. The percentage of carbon that it possesses and how it is distributed in iron has a direct impact on its physical properties and its behavior against different temperatures.
It is one of the metals with more applications in the industry; Among other things, it is used to manufacture:
* e tools instruments used, in turn, to build cars and ships;
* the structural bases of the buildings, thanks to its great resistance;
* suspension and arch bridges, among others;
* contemporary art;
* Utensils of various types and small tools.
Copper is very ductile and malleable, and resists corrosion very well. In addition, it conducts heat and electricity. With regard to its applications, it is used to:
* manufacture cables and components of electrical appliances;
* coin coins;
* make ornamental objects and kitchen utensils;
* produce electrotypes;
* reinforce parts of certain wooden structures.
Tin is a silvery white metal that, if it is less than 13 ° C, turns grayish powder and is called gray tin. Among its main characteristics can be mentioned its vulnerability to strong acids and that emits a particular sound when folded (known as the tin shout).
Tin is also one of the metals with important applications, such as the following:
* It is used in the form of paper to wrap and preserve some foods;
* it serves to create condenser sheets, used in the electrical industry;
* protects the iron plate (also called tin, used to make containers and other containers) against oxide;
* It can be alloyed with other metals to obtain anti-friction materials, which are used in the manufacture of pads.
Aluminum is the most abundant metallic element, and it is mainly characterized by its lightness, being highly reactive, very electro positive and being able to reduce metal compounds to basic metals. When he comes into contact with the air hot, suffers from corrosion.
It is one of the most used metals in the industry, as it serves to:
* the construction of air and land transportation means;
* the manufacture of kitchen utensils, foil, wire and pistons of internal combustion engines;
* make wrappers;
* the foundry, since its tension and ductility are especially appreciated.