The chemical element is the kind of atoms with the same nuclear charge

The concept of "chemical element" has long been usedscientists. So, in 1661 R. Boyle uses this definition for substances that, in his opinion, it is already impossible to decompose into simpler components - corpuscles. These particles do not change during chemical reactions and can have different sizes and masses.

Later, in 1789, Lavoisier proposed the first table, which includes 33 simple bodies. At the beginning of the ХІХ century. J. Dalton introduces the atomic-molecular hypothesis, on the basis of which J. Berzelius subsequently determines the atomic masses of the then known elements. In 1869, D.I. Mendeleev opens the periodic system (PS) and the periodic law. However, the modern interpretation of this concept was formed later (after the discoveries of G. Mosely and J. Chadwick). In their works, scientists have proved that the charge of the nucleus of an atom is equal to the corresponding (ordinal) number of the element in the PS DI. Mendeleev University. For example: Be (beryllium), ordinal number - 4, nuclear charge - +4.

These discoveries and scientific works helped to makethe conclusion that a chemical element is a kind of atoms with the same charge of nuclei. Consequently, the number of protons in them is the same. Now we know 118 elements. Of these, 89 are found in nature, and the rest are synthesized by scientists. It is worth noting that the International Chemical Union (IUPAC) officially recognized only 112 elements.

Every chemical element has the name andsymbol, which (together with the serial number and relative atomic mass) are recorded in the PS DI. Mendeleev University. The symbols used to record the types of atoms with an equal charge of the nucleus are the first letters of their Latin names, for example: oxygen (latin oxygen) -O, carbon (latin carbon) -C, etc. If the name of several elements starts with the same letter, another letter is added to its shortened entry, for example: lead (Latin plumbum) - Pb. These designations are international. New superheavy types of atoms with the same charge of nuclei, which were discovered in recent years and not officially recognized by IUPAC (numbers 113, 115-118) have temporary names.

The chemical element can be in the form ofsimple matter. Note that the names of simple substances may not coincide with the names of the type of atoms with the same charge of nuclei. For example, He (helium) exists in nature in the form of a gas, the molecule of which consists of one atom. The phenomenon of allotropy can also occur when one element can exist in the form of several simple substances (oxygen O₂ and ozone O_3). There is also a phenomenon of polymorphism, that is, the existence of several structural varieties (modifications). An example is a diamond, graphite.

Also, in their properties, types of atoms with equalThe charge of the nucleus is divided into metals and nonmetals. So, the chemical element metal has a special crystal lattice and most often in chemical reactions gives out external electrons, forming cations, and nonmetal - connects particles, forming anions.

During the course of chemical reactions, the element is preserved, since there is only a redistribution of elementary particles on external shells, and the nuclei of atoms themselves remain unchanged.

It turns out that the chemical element is a collection of a certain sort of atoms with the same charge of nuclei and the number of protons that exhibit characteristic properties.

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