DEFINITION OFMOLECULE:
The molecule is the smallest particle that has all the physical and chemical properties of a substance, and is formed by two or more atoms. The atoms that make up the molecules can be the same (as with the oxygen molecule, which has two oxygen atoms) or different (the water molecule, for example, has two hydrogen atoms and one oxygen atom).
The molecules are in constant movement, and this is known as molecular vibrations (which can be tension or bending). Their atoms are held together because they share or exchange electrons.
It should be noted that the molecules can be neutral or have an electrical charge. In the latter case, they are called ion-molecule or polyatomic ion.
Organic chemistry or carbon chemistry is a branch of chemistry that is responsible for analyzing those molecules that contain carbon and that form carbon-carbon or carbon-hydrogen covalent bonds, which are also called organic compounds.
Inorganic chemistry, on the other hand, is dedicated to the study of the formation, composition, structure and reactions of compounds and inorganic elements. There is also organometallic chemistry, which focuses on chemical compounds that have a bond between a carbon atom and a metal atom.
Biochemistry, on the other hand, is responsible for studying living beings at the molecular level. In this way, it analyzes the molecules that make up cells and tissues and that allow chemical reactions such as photosynthesis and digestion, among others.
Complex fullerenes
At the beginning of 2013, a group of scientists from the Institute of Astrophysics of the Canary Islands found unprecedented evidence of molecules whose complexity exceeded what was observed until then in the cosmos: the complex fullerenes, also known with the peculiar name of "carbon onions" . This discovery has a considerable impact on the fields of chemistry and physics of the Universe.
These are molecules of three dimensions that have great stability and resistance. With respect to their constitution, they are formed only by carbon atoms, mainly by C60 and C70; in the fullerenes that have atoms of the first type, hexagonal and pentagonal forms are observed, while in the second, oval designs are seen, of a softer and less angular surface.
In addition, the molecules found by these researchers are of a considerable size and have several complex layers, with more types of carbon than those mentioned above, such as C240 and C540. Another interesting data that throws the investigation, for which the process of astronomical observation was necessarily combined with theoretical knowledge of physics, is that the C60 fullerenes (the most common) have been found around two planetary nebulae of the Milky Way, which It can mean that these molecules with such characteristic shapes are more normal and abound more than previously believed.
With respect to the name of fullerenes, they derive from the surname of Richard Buckmister Fuller, who created the geodesic dome (part of a sphere formed by two-dimensional geometric figures). Its discovery dates back to the 80s and it was worthy of a Nobel Prize for the two professionals involved, but just after the first decade of this millennium, NASA discovered its presence in our galaxy, a fact that gave them back their validity, since their study can reveal fundamental information about the origin of our own existence.
Precisely, there is a theory that compares fullerenes with "cages" that carry other molecules and atoms, and it is believed that they have brought to Earth the substances that gave birth to life as we know it today.
Empirical Formulas and Molecular Formulas:
Chemists use chemical formulas to express the composition of molecules and ionic compounds, by means of chemical symbols. Composition means not only the elements present, but also the proportion in which the atoms are combined. It is necessary to become familiar with two types of formulas: molecular formulas and empirical formulas.
Molecular formulas:
A molecular formula indicates the exact number of atoms of each element that are present in the smallest unit of a substance.
In the analysis on molecules, each example is presented with its molecular formula. Thus H2 is the molecular formula of hydrogen, O2 represents oxygen, O3 is ozone and H2O represents water. The numerical subscript indicates the number of atoms of each element that are present. In the case of H2O, there is no subscript for the O because there is only one oxygen atom in a water molecule; in this way the subscript "one" of the formulas is omitted. Note that oxygen (O2) and ozone (O3) are allotropes of oxygen.
An allotrope is one of two or more different forms of an element.
Two allotropic forms of the element carbon-diamond and graphite-are completely different not only in their chemical properties, but also in their relative cost.
Molecular models:
Although it may seem like a toy for small children, in reality, molecular models are a caffeine_model_molecular tool vital to the study of chemistry as a calculator is for mathematics. And like any tool, the more you use it, the better it will serve you. Molecular models are intended to stimulate the imagination and help in the visualization process. That is, what they do is present a solid form of an abstract object that otherwise would have to be formulated in the mind or in a written text. Chemistry textbooks contain graphic language to describe molecules and reactions, however, what molecular models do is to improve understanding through a visual and, at the same time, tangible association.
In addition to using the models to examine the links between the atoms and the conformations of the molecules, they are especially useful for examining the arrangement of the atoms that make up the molecule in space, that is, its stereochemistry. If you are like me, you have a hard time imagining the structures of any molecule in a three-dimensional way, being able to see it with one of these models helps a lot.
I give you as an example something of geometry or molecular structure that, as you know, is the three-dimensional arrangement of atoms that make up a molecule. Compounds that differ from each other only in the spatial arrangement of their atoms are called stereoisomers. Stereoisomers that can not be easily interconverted by rotation around a bond are called isomer configurations and those that are readily interconverted by rotation around a bond are called conformational isomers. Certain isomeric configurations in the past (and some still today) were called geometric isomers. All this seems complicated, right? But everything is simplified enough when you can physically create these structures and visually check their geometry.
Only links are shown, such as thick lines. This model is suitable for viewing the structure of large molecules.
The chemical formulas:
Compound substances are represented by a combination of chemical symbols of the elements that constitute them. This form of representation, introduced by the Swedish chemist Jöhn J. Berzelius, has a double meaning, because it not only indicates what elements are present in a given compound, but also in what proportion the respective atoms participate in the formation of its molecule.
Each symbol in a chemical formula is equivalent to an atom of the corresponding simple substance. The subscripts that can appear in a formula refer to the number of atoms in each molecule. If the mass of the atoms is taken into account, the formula of a chemical combination also expresses the proportion by mass in which the elements intervene forming a given compound substance.
Thus, the ammonia formula, NH3, indicates that this substance results from the combination of hydrogen and nitrogen at the rate of three hydrogen atoms per nitrogen, or, in other terms, in the proportion of 3 x 1.008 grams of hydrogen for every 1 x 14,007 grams of nitrogen.
This type of formula, also called empirical or molecular formula, does not, however, indicate anything about the structure of the molecule; that is, about the way in which their component atoms and the links between them are distributed in the molecule.
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