What is Atomo? »Its Definition and Meaning [2019]

An Atomo is the smallest unit of particles that can exist as a simple substance (chemical element), and that can intervene in a chemical combination. Its term in Greek means "not divisible" ”, proposed by Democritus and Leucipo, who assumed that the matter was made up of indivisible and indestructible particles.

Over the centuries, the size and the The nature of the atom was only the subject of speculation, so its knowledge progressed very slowly.In the 16th and 17th centuries it was the beginning and development of experimental chemistry, where the English scientist John Dalton proposed that the matter is formed by atoms to which I assign a characteristic mass and differ from an element, and represent them as solid and indivisible spheres.

Later the English physicist JJThomson with the help of the use of rays cathodic, proposed a simple model of ca negative electrical gases (electrons) inside a positive sphere. Rutherford stated that there is a positively charged nucleus in the atom and electrons located in a crust spinning around it , as a solar system.

Similarly, the physicist Danish Bohr extended the Rutherford model, concluding that the electron revolves around the nucleus in circular orbits and the crust was composed of energy levels. Later Sommerfeld proposed that the electron tour is in elliptical and non-circular orbits.

All these investigations of the atomic model conclude that the structure of the atom is formed by a central part (nucleus) , provided with particles with positive charge (protons) and in turn with neutral charges (neutrons) ; and by an external part (crust or crown) , provided by negatively charged particles (electrons).

From the atomic nucleus, the following are derived properties: the atomic number (Z) , which is the number of protons in the nucleus of the atom, and the position that an element occupies in the periodic table; the atomic mass or mass number (A) , which is the total number of protons and neutrons present in the nucleus.

There are nuclei of the same element that contain the same number of protons but differ in the number of neutrons or mass, known as isotopes .This difference in the number of neutrons does not affect the behavior of atoms, since the charge electrical or distinctive character, depends exclusively on the number of protons and electrons.

Another property in atoms is the radioactivity is known as the spontaneous disintegration of atoms of atomic mass generally high, with continuous emission of energy in the form of heat, light, radiation and different chemicals.

For example; uranium of atomic mass 238 spontaneously decomposes to become a radius of atomic mass 226, and by successive transformations its period of disintegration ends when it becomes lead.