It is called Periods of chemistry To the division by ages of the history of science in charge of studying the properties and transformations of matter. These periods comprise approximately four ages that start from prehistory and go until today.
Chemistry can be defined as the branch of science that studies the structure of matter, its composition, changes and, in general, its behavior. Chemistry can be classified into organic and inorganic depending on the composition of matter.
Man's interest in understanding the mysteries related to the transformation of matter dates back to the time of the Babylonian empire. For this reason, chemistry is considered as one of the oldest sciences (Poulsen, 2010).
In general, the chemical models most used by scientists today are based on principles and ideas conceived by the philosophers of ancient Greece as Aristotle or Democritus. These were the ones who proposed the idea of a particle called an atom, of which matter is composed.
The main periods of chemistry
Prehistory and antiquity (1700 BC - 300 BC)
The first evidence of a scientific dialogue held on issues related to chemistry occurred more than 3700 years ago in the Babylonian empire, when the king Hammurabi Wanted to classify all known metals into a list of heavy bodies.
Later, about 2500 years ago, Greek philosophers gave way to the first logical reasoning around matter. This early historical period of chemistry is called prehistory.
The Greek philosophers They claimed that the universe was composed of a single enormous mass compact. In other words, they believed that the universe was a unit of mass and that all objects and substances contained in the universe were connected to each other as unmodifiable elements (Trifiro, 2011).
In 430 BC, Democritus was the first philosopher to claim that matter was composed of small particles called atoms. Atoms were small, solid, invisible objects that shaped everything that occupies a physical place in the universe.
Subsequently, Aristotle would determine that there are several states of matter, and that this can vary in temperature and humidity. Aristotle stated that there are only four elements that make up matter: fire, air, water and earth.
Alchemist period (300 BC - 1600 AD)
This historical period begins with the influence of Aristotle and his approaches to the possibility of converting any metal into gold. The whole of these principles was called Alchemy and the substance necessary to carry out the process of conversion of metals into gold was called the Philosopher's Stone.
For more than 1500 years, the efforts of man were oriented to the exercise of chemical activities related to Alchemy.
Between the thirteenth and fifteenth centuries many individuals wanted to be part of the gold production industry, which is why Pope John XXII issued an edict against the manufacture of gold. Although the efforts of the alchemists were in vain, the gold production business continued for hundreds of years. (Katz, 1978)
The alchemist hobby reached a new level during the rebirth, when scientists not only aspired to turn any metal into gold, but also wanted to find the recipe to make a substance that would allow humans to live longer and cure any kind of disease . This substance was called the elixir of life and its manufacture was never possible (Ridenour, 2004).
At the end of the seventeenth century Robert Boyle published the first treatise on chemistry that rejected Aristotle's first idea of the classification of the elements that make up matter. In this way, Boyle destroyed all the concepts that have been so far on chemistry.
Theory of the Flogist (1600 - 1800)
This historical period of chemistry was called Flogisto, by the theory proposed by Johann J. Beecher who believed in the existence of a substance called phlogiston, which was the substance resulting from the combustion of matter that was able to pass to Another substance and adhere to it. In this way it was believed that adding phlogiston to certain substances could produce new ones.
During this period Charles Coulomb also discovered that the particles of matter have positive and negative charges. The force of attraction or repulsion of objects would depend on the charges contained by the particles of matter.
In this way scientists began to notice that the combination of two substances to produce a new substance would depend directly on their charges and their mass (Video, 2017).
During the eighteenth century the atomic theory as we know it today was also raised by Dalton. The conduction of experiments with various metals would allow Antoine Lavosier in this century to verify the atomic theory and later to propose the theory of conservation of matter, which indicates that matter is not created or destroyed, it simply transforms.
Modernity (1800 - present)
In the mid-nineteenth century Willian Crookes God first steps towards the definition of modern atomic theory. In this way Crookes identified the existence of cathode rays or currents of electrons with the help of the vacuum tube invented previously by Heinrich Geissler.
During this historical period, X-rays, the fluorescent light produced by compounds of pitchblende, radioactive elements and the first version of the periodic table were also discovered by Dmitri Mendeleyev.
To this first version of the periodic table was added multiple elements with time, including uranium and thorium, discovered by Marie Curie as components of the pitchblende (ColimbiaUniveristy, 1996).
periodic table of elements
At the beginning of the 20th century, Ernest Rutherford Determined that there are three types of radioactivity: alpha (+) particles, beta (-) particles and gamma (neutral) particles. The atomic model of Rutherford was developed and accepted, until today, as the only correct one.
Rutherford Atomic Model
The concepts of fusion and fission were also developed in the twentieth century by bombarding elements with neutrons and producing new elements with a higher atomic number. This allowed the development of new radioactive elements artificially created in a laboratory.
Albert Einstein was a spokesman for research and experimentation with radioactive elements, contributing to the development of the first fission nuclear reactor that would later lead to the birth of the atomic bomb (Janssen, 2003).
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