The links are the union that exists between the various molecules that form matter, they are the force between two or more atoms, it is what keeps the molecules together, when an approach between atoms of the same element or different elements occurs. .
In the bonds there are forces of attraction between the electrons of these atoms and the nucleus of one or another atom, a force of attraction that is variable, where depending on whether this force is large enough, bonds may or may not be formed. chemicals between the atoms of the elements involved, thus forming the great diversity of molecules in the universe.
The types of links are:
There are four types of chemical bonds, ionic bonds, covalent bonds, and metallic bonds. The same that can be subdivided into subtypes, as in the case of Intermediate covalent bonds and Coordinate covalent bonds.
The ionic bond is the electrostatic union between two atoms, which have lost and gained electrons respectively. These links occur when the atoms that interact with each other have a large difference in electronegativity, which is usually greater than 1.7. In this way, the element with the highest electronegativity, (a non-metal), takes the pair of electrons, transforming both into ions, which are held together due to electrostatic attraction, resulting in salts.
It is emphasized that ionic bonds occur between a metal and a non-metal, they usually take the form of crystals, and they are generally soluble in water, have high electrical conductivity and a high melting and boiling temperature.
Covalent bonds are those that are made from the union that occurs between non-metals, which share the bonding electrons, achieving greater stability by forming an octet between both atoms. This type of bond occurs when the electronegativity present is less than 1.7 or null.
As a consequence of the variations in the electronegativity of this type of bonds, three types or subtypes of covalent bonds are distinguished: polar covalent bonds, nonpolar covalent bonds, and coordinate covalent bonds.
1.- Covalent to polar bond.- The covalent to polar bond occurs when the difference in electronegativity is close to zero. The electrons of these bonds are equidistant between both atoms, sharing them equally. It is a type of bond that usually occurs between atoms of the same element, it is the case, for example, of molecular oxygen, although it can also be the case, in molecules whose electronegativity is similar.
2.- Polar covalent bond.- In it the bonding electrons are shared unequally by the atoms, in this case the atom with the highest electronegativity attracts the bonding electrons to it, but unlike ionic bonds, these Electrons are not completely removed from the other atom.
3.- Coordinate or dative covalent bonds.- They are those that occur when an element with two electrons gives up a pair of electrons to another highly electronegative element.
They are the bonds that occur only between metallic atoms, and of the same type, unlike the other types of bonds, which occur between two atoms, metallic bonds occur within a set of atoms. All the atoms that participate intertwining, contribute electrons that are not “fixed” in any particular atom, but form an electronic “cloud“, which have free movement within the entire material (metal). It is highlighted that most of the cases the substances that have metallic bonds, are in a solid state at room temperature (except mercury), have “metallic shine” and their melting and boiling temperatures are extremely high compared to substances with other types of link, as well, have very high thermal and electrical conductivity.