At the moment, science knows one hundred and five chemical elements, systematized in the form of a periodic table. The vast majority of them are classified as metals, which implies that these elements have special qualities. These are the so-called metallic properties. Such characteristics, first of all, include plasticity, increased thermal and electrical conductivity, the ability to form alloys, and a low ionization potential.
The metallic properties of an element are due to the ability of its atoms, when interacting with the atomic structures of other elements, to displace electron clouds in their direction or “give away” their free electrons to them. The most active metals are those that have low ionization energy and electronegativity. Also, pronounced metallic properties are characteristic of elements that havethe largest atomic radius and the smallest possible number of external (valence) electrons.
As the valence orbit fills up, the number of electrons in the outer layer of the atomic structure increases, and the radius, accordingly, decreases. In this regard, the atoms begin to strive for the attachment of free electrons, and not for their return. The metallic properties of such elements tend to decrease, and their non-metallic properties tend to increase. Conversely, with an increase in the atomic radius, an increase in metallic properties is noted. Therefore, a characteristic common feature of all metals is the so-called reducing qualities - the very ability of an atom to donate free electrons.
The most striking metallic properties of elements are manifested in substances of the first, second groups of the main subgroups of the periodic table, as well as in alkali and alkaline earth metals. But the strongest reducing properties are observed in francium, and in the aquatic environment - in lithium due to a higher hydration energy.
The number of elements that exhibit metallic properties within a period increases with the number of the period. In the periodic table, metals are separated from non-metals by a diagonal line that runs from boron to astatine. Along this dividing line are elements in which both qualities are equally manifested. Such substances include silicon, arsenic, boron, germanium, astatine, antimonyand tellurium. This group of elements is called metalloids.
Each period is characterized by the presence of a kind of "border zone" in which elements with dual qualities are located. Consequently, the transition from a pronounced metal to a typical non-metal is gradual, which is reflected in the periodic table.
The general properties of metal elements (high electrical conductivity, thermal conductivity, malleability, characteristic luster, plasticity, etc.) are due to the similarity of their internal structure, or rather, the presence of a crystal lattice. However, there are many qualities (density, hardness, melting point) that give all metals purely individual physical and chemical properties. These characteristics depend on the structure of the crystal lattice of each particular element.
