We take daily contact with many substances consisting only of metal atoms, called metal substances. Among the best known examples are iron, aluminum, lead, copper and silver.
How do atoms come together to form these substances?
Let's look at the atom model below. The negatively charged electrons are attracted to the nucleus, in which, besides the neutrons, are the positively charged protons. The attraction that the positively charged nucleus exerts on the electrons is responsible for the fact that these electrons remain in the atom rather than leave it.
An idea similar to this can be used to imagine the bond between metal atoms, called metal connection.
Consider a sample of the simple silver substance. It is formed by a cluster of many silver chemical atoms. In this cluster, each atom is surrounded by other atoms just like it. The nucleus of each atom is attracted to the electrons of its electrosphere and also to the electrons of neighboring atoms, holding the whole structure together.
The electrons, in turn, are not fully attached to just one atom and can “transit” throughout the structure. Some scientists use the term “sea of electrons” to designate this situation.
Metallic substances (or simply metals) are useful to humans because of their properties, which are quite generally listed below.
- Characteristic brightness. When polished, metals reflect light very well. This property is easy to see on trays and silver mirror.
- High thermal and electrical conductivity. These properties are due to free electrons. The orderly movement of the electrons constitutes the electric current and their agitation allows the rapid programming of heat through the metallic substances.
- High melting and boiling points. These are generally metal characteristics (although there are exceptions such as mercury, PF = -39 ° C; gallium, PF = 30 ° C, and potassium, PF = 63 ° C). Due to this property and also the good thermal conductivity, some metals are used in cookware and car radiators.
- Malleability. Metals are very malleable, ie easy to turn into blades. The most malleable metal is gold, which makes it possible to obtain the thinnest blades.
- Ducibility. Metals are also very ductile, that is, easy to turn into wires. Gold is also the most ductile of metals, allowing it to obtain very fine wires.