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Put forward atomic model in: 340~ B.C (Estimated)

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During the Classical period in Ancient Greece, Aristotle was a Greek philosopher and polymath. He was the founder of the Lyceum, the Peripatetic school of philosophy, and the Aristotelian legacy, and also was taught by Plato.

Aristotle was an agnostic who did not believe in the atomic theory and taught as such. He believed that all materials on Earth were formed out of the four elements: Earth, Fire, Water, and Air, rather than atoms. He thought that all matter consists up of tiny amounts of these four dimensions.

It is unclear how Aristotle came up with his atomic theory. His theory was the most popular and widely acknowledged ancient theory on atoms.

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Democritus, a Greek who lived from 460 BCE to 370 B.C., fostered another hypothesis of his own; his ideals relied  on thinking instead of science

Democritus' model expressed that matter consisted of undetectable particles called atoms. He also expressed that molecules are indestructible and unchangeable. Additionally that they are homogenous, which means they have no inside structure.

Democritus realized that if you took a stone and cut it down the middle, every half had the equivalent properties as the first stone. He contemplated if you kept on cutting the stone into smaller pieces, sooner or later you would turn into a piece so small that it could not be partitioned anymore

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A diligent experimenter named Antoine-Laurent Lavoisier revolutionized chemistry. Among his many contributions, he established the rule of conservation of mass, discovered that combustion and respiration are driven by chemical interactions with what he called "oxygen," and contributed to the systematization of chemical nomenclature.

Between 1772 and 1794, the French chemist Antoine Lavoisier made the first breakthrough in the study of chemical processes. In a chemical reaction, Lavoisier discovered that mass is conserved. The entire mass of a chemical reaction's products is always the same as the total mass of the reaction's starting components. His findings led to one of chemical behavior's most fundamental laws: the law of conservation of matter, which asserts that matter is conserved in chemical reactions.

Lavoisier estimated that water contained around 85 percent oxygen and 15 percent hydrogen by weight in his famous textbook, Trait lmentaire de Chimie, published in 1789. As a result, water appeared to have 5.6 times more oxygen than hydrogen by weight.

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John Dalton FRS was a chemist, physicist, and meteorologist from England. He is well known for introducing the atomic theory into chemistry and for his color blindness study, which is frequently referred to as Daltonism after him.

A hypothesis of chemical combination, expressed by John Dalton includes the accompanying postulates:
(1) Elements comprise resolute little particles (atoms).
(2) All atoms of a similar type are indistinguishable; various components have various sorts of atoms.
(3) Atoms cannot be made nor destroyed.
(4) 'Compound elements' (i.e. compounds) are framed when molecules of various components participate in straightforward proportions to shape 'compound atoms' (i.e. molecules). Dalton additionally proposed images for atoms of various elements (later supplanted by the current documentation utilizing letters).

Dalton fostered the law of numerous extents (first introduced in 1803) by examining and developing the efforts put forward by Antoine Lavoisier and Joseph Proust. Proust had concentrated on tin oxides and discovered that they would always be in proportion of 1:2. Dalton tracked down a nuclear hypothesis of issue that could exquisitely clarify this normal example in science – on account of Proust's tin oxides, one tin particle will join with possibly a couple of oxygen molecules.

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J.J. Thomson attended Cambridge Trinity College and went to manage the Cavendish Lab. His study in cathode rays led to the electron's discovery and he explored additional breakthroughs in an examination of nuclear structures. Among numerous awards, Thomson was awarded the 1906 Nobel Prize for Physics.

Thomson argued that the atom model is a sphere that has positive matter, in which electron forces are placed.

Thomson has put two opposing electric plates surrounding the cathode ray, to investigate the characteristics of the particles. The cathode ray was moved from the negative electrical plate to the positive plate. This showed that the cathode ray consisted of particles with a negative charge.

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Ernest Rutherford, 1st  Baron Rutherford was a British scientist born in New Zealand who became renowned as the "Father of Nuclear Physics." According to Encyclopaedia Britannica, he is the best experimentalist since Michael Faraday.

The Rutherford model, also known as the Rutherford atomic model, nuclear atom, or planetary model of the atom, is a description of atom structure presented by Ernest Rutherford, a New Zealand-born scientist. The concept depicted the atom as a small, compact, positively charged center called a nucleus, in which virtually all of the mass is concentrated, and around which the light, negative components known as electrons revolve at a distance, similar to planets orbiting around the Sun.

Sir J.J. Thomson's conception of the atom as a uniformly dispersed material was refuted by Rutherford in 1909. Rutherford deduced that the gold atom's mass must be concentrated in a tiny compact nucleus since only a small percentage of the alpha particles in his beam were dispersed by significant angles after striking the gold foil, while the majority went perfectly through.

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Niels Henrik David Bohr was a Danish scientist who earned the Nobel Prize in Physics in 1922 for his contributions to understanding atomic structure and quantum theory. Bohr was a philosopher as well as a proponent of scientific study.

Following the discovery of the electron and radioactivity in the late 1800s, several theories for the structure of the atom were presented. Niels Bohr presented a hypothesis for the hydrogen atom in 1913, based on quantum theory, which states that some physical quantities have only discrete values. Electrons travel around a nucleus in predetermined orbits, and if they leap to a lower-energy orbit, the energy difference is radiated. Bohr's model explained why atoms only emit light with fixed wavelengths and subsequently included light quanta ideas.

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Erwin Schrödinger was an Austrian theoretical physicist who made contributions to quantum mechanics' wave theory of matter and other foundations. He's also the notorious Austrian who came up with the famous thought experiment about a cat in a box that might be alive and dead at the same time, according to quantum physics.

The Schrödinger equation, which defines how the wave function of a quantum mechanical system (in this example, a hydrogen atom's electron) develops, was used by Erwin Schrödinger to compute the quantization of the hydrogen atom's energy levels that appeared in Niels Bohr's atomic model.

Schrödinger proposed a theory describing the behavior of such a system by a wave equation that is now known as the Schrödinger equation, based on a suggestion made by Louis de Broglie in 1924 that particles of matter have a dual nature and in some conditions operate like waves. Unlike Newton's equations, Schrödinger's equation solutions are wave functions that can only be linked to the likelihood of physical events occurring.

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James Chadwick was an English physicist and Nobel winner in physics. Under the supervision of Ernest Rutherford, James Chadwick started his studies at the University of Manchester.

James Chadwick revealed in May 1932 that the core also contained the new uncharged, called the neutron.

James Chadwick performed an experiment whereby the natural radioactive decay Polonium attacked Beryllium with the alpha particles. The resultant radiation exhibited substantial penetration through a lead shield, which cannot be explained by the known particles.

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