The 5 types of chemical bonds: this is how matter is composed
The cells of our body, the air, the water, the different minerals ... each and every one of the elements that surround us they are made up of different types of atoms and molecules . These particles are the basic unit of matter and, in addition, serve to understand how many biological processes related to neurosciences, such as depolarization, occur.
However, in order to form something as complex as a living organism or the various compounds or materials that we observe in our day to day, it is necessary that the atoms are grouped and related in some way. From the chemistry the composition of the matter has been studied, including the elements that allow the different atoms to be linked. It is about the so-called chemical bonds.
In this article let's see how the main types of chemical bonds are present in nature.
- Related article: "The 15 types of energy: what are they?"
The chemical bond
It is understood by chemical bond that interaction or force that generates two or more atoms to maintain a union based on the transmission of electrons between both.
The electrons of the outermost layers of the atom are attracted by the electrical charge that the atoms that surround it, specifically its nucleus. And although the nuclei repel each other by having both positive charge, the electrons (negatively charged) of each of the atoms are attracted by the core of the other.
Depending on the position of both, the electronegativity or difficulty of ionizing the atom and the electronic stability that each atom already possesses, it is possible that the force of the attraction between the electron and the nucleus prevents a repulsion between atoms. A chemical bond will be created in which one of the atoms will lose electrons and the other will gain them, achieving a final state in which the set of the two atoms reaches a stable electric charge level.
- Related article: "The 9 postulates of Dalton's atomic theory"
Main types of chemical bonds between atoms
Below you can see what are the three main types of chemical bonds through which the different atoms come together to form the different molecules. One of the main differences between them are the types of atoms that are used (metallic and / or non-metallic, being the metallic little electronegative and the non-metallic much).
1. Ionic link
The ionic is one of the best known types of chemical bonds , being the one that is formed when a metal and a non-metal are joined (that is, a component with little electronegativity with one with a lot).
The outermost electron of the metallic element will be attracted by the core of the non-metallic element, the second one yielding the electron to the first. Stable compounds are formed, whose union is electrochemical. In this union the non-metallic element becomes anion when finally being negatively charged (after receiving the electron), while the metals become positively charged cations.
A typical example of ionic bonding is found in salt, or in crystallized compounds. The materials formed by this type of union tend to require a large amount of energy to melt them and are usually hard, although they can easily compress and break. In general they tend to be soluble and can be easily dissolved.
2. Covalent links
The covalent bond is a type of bond characterized in that the two atoms to be joined have similar or even identical electronegative properties. The covalent bond means that both atoms (or more, if the molecule is made up of more than two atoms) share the electrons among themselves, without losing or gaining in quantity.
This type of links is the one that usually forms part of the organic matter, such as the one that configures our organism, and they are more stable than the ionic ones. Its melting point is lower , to the point that many compounds are in a liquid state, and are not usually conductors of electricity. Within the covalent bonds we can find several subtypes.
Non-polar or pure covalent bond
It refers to a type of covalent bond in which two elements are joined with the same level of electronegativity and whose union does not cause one of the parts to lose or gain electrons, being the atoms of the same element . For example, hydrogen, oxygen or carbon are some elements that can be attached to atoms of the same element to form structures. They are not soluble.
Polar covalent bond
In this type of covalent bond, in fact the most usual one, the atoms that come together are of different elements. Both have a similar electronegativity although not identical, with which they have different electrical charges. Neither in this case are electrons lost in any of the atoms, but they share them.
Within this subgroup we also find the bipolar covalent bonds, in which there is a donor atom that shares the electrons and another or other receptors that benefit from this incorporation.
Things as basic and essential for us as water or glucose are formed from this type of link.
3. Metallic link
In metal bonds two or more atoms of metal elements are joined together. This union is due not to the attraction between the two atoms to each other, but to a cation and the electrons that have been free and foreign making it such a thing. The different atoms configure a network around these electrons, with patterns that are repeated. These structures tend to appear as solid and consistent elements , deformable but difficult to break.
Also, this type of link is linked to the electrical conductivity of metals, as their electrons are free.
Chemical bonds between molecules
Although the main chemical bonds are the previous ones, At the molecule level we can find other modalities . Some of the main and best known are the following.
4. By Van der Waals forces
This type of union occurs between symmetrical molecules and act as a function of the attraction or repulsion between molecules or the interaction of ions with molecules. Within this type of unions we can find the union of two permanent dipoles , two dipoles induced or between permanent and induced dipole
5. Hydrogen bond or hydrogen bridge
This type of bond between molecules is an interaction between hydrogen and another element of high polarity. In these links the hydrogen has a positive charge and is attracted by polar electronegative atoms , generating an interaction or bridge between both. Said union is considerably weak. An example is found in water molecules.
Bibliographic references:
- Chamizo J. A. (2006). The chemistry models, Chemical Education, 17, 476-482.
- García, A .; Garritz; A. and Chamizo, J.A .. (2009). Chemical bond. A constructivist approach to his teaching.
