Pauli Exclusion Principle

Over the course of the last 5000 years, mankind’s knowledge has been constantly advancing. Chemistry, a branch of science, has experienced a tremendous leap and expansions since ancient Greek civilization. One of the major breakthroughs in the advancement in Chemistry was the creation of the Atomic theory, which laid a foundation for the modern-day Chemistry and future of science. The Atomic theory introduced the idea of atoms, which are defined as the discrete units of matter. There are five key scientists that significantly contributed to the Atomic model over a span of thousands of years. They are: Democritus, John Dalton, J.J. Thompson, Ernest Rutherford, and Niels Bohr.

Explained how electrons move in wave formation and developed the ‘Shrodinger equation’ that describes how the quantum state of of a system changes with time.

In a long line of the Bohr Family line as great physicists the most exemplary member in the authors opinion is Mr. Niels Bohr of Denmark. He took great advice from both great past

Principle”. The French team of Pierre and Marie Curie who are known as the parents of nuclear physics came to the realization that the atom has a core, or nucleus. It became apparent that different laws of physics govern the nucleus. In Cambridge England, Sir J.J. Thomson who in 1897 discovered the electron and his pupil Lord Ernest Rutherford discovered the proton. The history of the atomic age was coming right along on a steady pace then in 1905 Albert Einstein wrote the mass-energy conversion equation, and things started to progress very rapidly. In 1932 Sir James Chadwick discovered the neutron, this rovided an ideal projectile for splitting the atom. The final clue to the neutron and atomic energy was when an observation was noted that a peculiar property of the radiation emitted when beryllium is bombarded with alpha particles. In 1938 the discovery of fission of the uranium nucleus by neutron bombardment. In 1940 President Roosevelt organized the National Defense Research Committee, which was determined to develop an atomic bomb. Development and construction of the atomic bomb was the most closely guarded secret in scientific history. This was a

He discovered the electron and experimented by testing the electric discharge in a high vacuum cathode ray tube. (Nobel Lectures.1967)

The Daltons research papers changes, he began to study and observe the physical sciences: heat conduction, gas expansion by heat, the properties of light, the aurora borealis, and meteorology. These studies helped him establish The Atomic Theory. Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.Dalton's atomic theory also stated that all compounds were composed of combinations of these atoms in defined ratios.Dalton also postulated that chemical reactions resulted in the rearrangement of the reacting atoms. Terms atom The smallest possible amount of matter that still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons. atomic mass unit The standard unit that is used for indicating mass of an

Over the past millennia, our understanding of the atom has evolved through eager hypothesizing, numerous trials and startling discoveries. From the first atomic theories of the Democritus in Ancient Greece to the gold foil experiment that allowed Ernest Rutherford to discover the atomic nucleus in 1909, humanity has come far on the path to crack the mysteries of the atomic structure and the hidden secrets that lie within. However, it was only in the 1930s that the full basic structure of the atom was finally completed with the discovery of the neutrally charged particle known as the neutron.

3) Atoms of a particular element are identical in mass, size, shape and other properties.

| An atom is the smallest "piece" of an element that still has the properties of that element. A molecule is a combination of two or more |

Atomic theory is the theory that all matter is made up of tiny indivisible particles called atoms. This paper will discuss its beginnings and some of the scientists who made major contributions to how it is defined today.

If the scientists improved each other’s theories, then these improved theories helped to create the modern atomic theory.

Prior to the research of JJ Thomson and Ernest Rutherford a theory pertaining to atoms and a model was already created. A scientist named John Dalton performed experiments using chemicals that showed elementary particles that were later discovered to be atoms. Which led to the creation of his theory that everything is made of atoms and that atoms were the smallest form of matter. This was investigated overtime as scientists investigated elements and connected between the two. The discoveries found led to technological methods which were inventions created to find information about atoms that both JJ Thompson and Ernest Rutherford later used to prove and disprove their theories. The most important invention being the cathode ray tube which show rays were traveling in straight lines and an electric charge that passed from the tube to the wires demonstrated by the glow on the walls of the tube. This information became the basis for both JJ Thomson and Ernest

The main points of Dalton’s atomic theory, an explanation of the structure of matter in terms of different combinations of very small particles, are given by the following postulates:

With this remarkable paper, he was the recipient of the medal from the Royal Danish Academy of Sciences. According to Oppenheim, his research topic was based on his analysis of vibrations of water, due to surface tension. After this, he completed his doctorate in 1911, under the physicist Christian Christiansen. For his post-doctoral education, Bohr moved to England. He conducted his experiments at Trinity College, and then moved on to the University of Manchester. While at the University of Manchester, he began his interest in the structure of the atoms. He wanted to know what was going on inside an atom. Bohr studied the way atoms behaved and came up with a model that gave an explanation.

In 1977, Mott received the Noble Prize for Physics, an honor which he shared with two other physicists. The prize was awarded for theoretical studies of the structure of the electron, regarding magnetic and disordered systems (Sir Neill F. Mott - Facts, 2015, para. 4).