4 PERIODS OF CHEMISTRY: FROM PREHISTORY TO TODAY - CHEMISTRY - 2024

Periods of chemistry are called the division by ages in 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 up to 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 from the Babylonian empire. For this reason, chemistry is considered 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 such as Aristotle or Democritus. It was these who proposed the idea that there was a particle called an atom, of which matter is composed.

The main periods of chemistry

Prehistory and antiquity (1700 BC - 300 BC)

The first evidences of a sustained scientific dialogue around topics related to chemistry occurred more than 3700 years ago in the Babylonian empire, when King Hammurabi wanted to classify all known metals in a list of heavy bodies.

Later, approximately 2,500 years ago, the Greek philosophers gave way to the first logical reasoning around matter. This first historical period of chemistry is called prehistory.

The Greek philosophers claimed that the universe was composed of a single huge compact mass. 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 unchangeable elements (Trifiró, 2011).

In 430 BC, Democritus was the first philosopher to claim that matter was made up of tiny particles called atoms. Atoms were small, solid, invisible objects that shaped everything that occupies a physical place in the universe.

Later, Aristotle would determine that there are several states of matter, and that it can vary in temperature and humidity. Aristotle declared 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 ideas about the possibility of converting any metal into gold. The set of these principles was called Alchemy and the substance necessary to carry out the process of converting 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 13th and 15th 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 alchemists' efforts were in vain, the gold production business continued for hundreds of years. (Katz, 1978)

The alchemist hobby reached a new level during the Renaissance, 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 type 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 ideas on the classification of the elements that make up matter. In this way, Boyle destroyed all the concepts that until now had been about chemistry.

Phlogiston theory (1600 - 1800)

This historical period of chemistry was called Phlogiston, after 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 capable of passing into another substance and stick 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 18th century the atomic theory as we know it today was also proposed by Dalton. Conducting experiments with various metals would allow Antoine Lavosier to verify the atomic theory in this century and later propose the theory of conservation of matter, which indicates that matter is neither created nor destroyed, it simply transforms.

Modernity (1800 - present)

In the mid-nineteenth century, Willian Crookes took the first steps towards defining modern atomic theory. In this way Crookes identified the existence of cathode rays or electron currents with the help of the vacuum tube previously invented by Heinrich Geissler.

During this historical period, X-rays, fluorescent light produced by pitchblende compounds, radioactive elements were also discovered, and the first version of the periodic table was created by Dmitry Mendeleev.

To this first version of the periodic table, multiple elements were added over time, including uranium and thorium, discovered by Marie Curie as components of 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. Rutherford's atomic model was developed and accepted, until today, as the only correct one.

Rutherford's atomic model

The concepts of fusion and fission were also developed in the 20th century, by bombarding elements with neutrons and producing new elements with a higher atomic number. This allowed the development of new artificially created radioactive elements in a laboratory.

Albert Einstein was a spokesperson for research and experimentation with radioactive elements, contributing to the development of the first nuclear fission reactor that would later lead to the birth of the atomic bomb (Janssen, 2003).

References

1. (nineteen ninety six). Colimbia Univeristy. Retrieved from History of Chemistry: columbia.edu
2. Janssen, M. (2003). Albert Einstein: His Biography in a Nutshell. Hsci / Phys 1905.
3. Katz, DA (1978). An Illustrated History Of Alchemy And Early Chemistry. Tucson: Splendor Solis.
4. Poulsen, T. (2010). Introduction to Chemistry. CK-12 Foundation.
5. Ridenour, M. (2004). Origins. In M. Ridenour, A BRIEF HISTORY OF CHEMISTRY (pp. 14-16). Awsna.
6. Trifiró, F. (2011). A History of Chemistry. Fundamentals of Chemistry, Vol 1, 4-5.
7. Video, A. (2017). Chemistry Timeline. Ambrose Video.