Uploaded by Annie Panteleeva

The history of chemistry

Chemistry has existed since ancient times. By 1000 BC, ancient civilizations used
technologies that would eventually form the basis of the various branches of chemistry. By that
time people could extract metals from ores, make pottery and glazes, ferment beer and wine,
extract chemicals from plants for medicine and perfume, render fat into soap, make glass, and make
alloys like bronze.
The history of chemistry is usually divided into several periods, such as Ancient history,
Medieval alchemy, Early chemistry and Modern chemistry.
The earliest recorded metal employed by humans seems to be gold, which can be found free
or "native" with the first appearance near 40.000 BC. Silver, copper, tin and meteoric iron can also
be found native, allowing a limited amount of metalworking in ancient cultures.
Arguably the first chemical reaction used in a controlled manner was fire that could
transform one substance into another (burning wood, or boiling water) while producing heat and
Certain metals can be recovered from their ores by simply heating the rocks in a fire: notably
tin, lead and copper, a process known as smelting (dated the 5th and 6th millennium BC). By
combining copper and tin, a superior metal could was made, an alloy called bronze.
The extraction of iron from its ore into a workable metal is much more difficult than copper
or tin.
Discovering new substances made philosophers questioning how to explain and rationalize
why different substances have different properties, exist in different states, and react in a different
manner when exposed to environments. Since the main elemental substances were fire, water,
earth and air, some considered them to be the base to other elements.
The protoscience of chemistry, alchemy, was unsuccessful in explaining the nature of matter
and its transformations. However, by performing experiments and recording the results, alchemists
set the stage for modern chemistry. Alchemists toiled to make transformations on spiritual and/or
practical level. Alchemy and chemistry share an interest in the composition and properties of
matter, and prior to the 18th century were not separated into distinct disciplines.
However, the era of alchemy ended, and so scientist tried to explain known reactions and
experiments by discovering new laws.
English chemist Robert Boyle is regarded today as the first modern chemist, and therefore
one of the founders of modern chemistry, and one of the pioneers of modern experimental scientific
method. Although Boyle was not the original discover, he is best known for Boyle's law, which he
presented in 1662: the law describes the inversely proportional relationship between the absolute
pressure and volume of a gas, if the temperature is kept constant within a closed system.
Antoine-Laurent de Lavoisier, a French chemist, described the boiling of water and the
burning of substances.
is also celebrated as the "father of modern chemistry". Lavoisier demonstrated with careful
measurements that transmutation of water to earth was not possible, but that the sediment
observed from boiling water came from the container. He burnt phosphorus and sulfur in air, and
proved that the products weighed more than the original. Nevertheless, the weight gained was lost
from the air. Thus, in 1789, he established the Law of Conservation of Mass, which is also called
"Lavoisier's Law."
Then there came the 19th century, when scientist tried to explain the structure of elements.
Hence, in 1803, English meteorologist and chemist John Dalton proposed a modern atomic
theory in 1803 which stated that all matter was composed of small indivisible particles termed
atoms, atoms of a given element possess unique characteristics and weight, and three types of
atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules).
Describing his own observations of gasses, in 1811 the Italian physicist Amedeo Avogadro
hypothesized that equal volumes of gases at the same temperature and pressure contain equal
numbers of molecules, from which it followed that relative molecular weights of any two gases are
the same as the ratio of the densities of the two gases under the same conditions of temperature
and pressure.
An important breakthrough in making sense of the list of known chemical elements (as well
as in understanding the internal structure of atoms) was Dmitri Mendeleev's development of the
first modern periodic table. Mendeleev found that, when all the known chemical elements were
arranged in order of increasing atomic weight, the resulting table displayed a periodicity of
properties within groups of elements. So he built up a systematic periodic table of all the 66
elements then known based on atomic mass. His first Periodic Table was compiled on the basis of
arranging the elements in ascending order of atomic weight and grouping them by similarity of
Marie Skłodowska-Curie was a Polish-born French physicist and chemist who is famous for
her pioneering research on radioactivity. She and her husband Pierre are considered to have laid
the cornerstone of the nuclear age with their research on radioactivity. She discovered that the rays
remained constant, no matter the condition or form of the uranium.
New Zealand-born chemist and physicist Ernest Rutherford is considered to be "the father of
nuclear physics." Rutherford is best known for devising the names alpha, beta, and gamma to
classify various forms of radioactive "rays" which were poorly understood at his time.
In 1913, Niels Bohr, a Danish physicist, introduced the concepts of quantum mechanics to
atomic structure by proposing what is now known as the Bohr’s model of the atom, where electrons
exist only in strictly defined circular orbits around the nucleus similar to rungs on a ladder.
After the discovery by Rutherford and Bohr of the atomic structure in 1912, and by Marie
and Pierre Curie of radioactivity, scientists had to change their viewpoint on the nature of matter.
The experience acquired by chemists was no longer pertinent to the study of the whole nature of
matter but only to aspects related to the electron cloud surrounding the atomic nuclei and the
movement of the latter in the electric field induced by the former.
Hence, chemistry can be considered as the oldest science, playing the great role in our
everyday life.