The Development Of Atomic Structure And Theory Environmental Sciences Essay

Ernest Rutherford ‘s important accomplishments began in 1886 when he invented a sensor of electromagnetic moving ridges during a research undertaking to derive entree into the University of Cambridge. Rutherford ‘s setup for observing electromagnetic moving ridges was simpler than Heinrich Hertz ‘s and had commercial potency. In 1896, shortly after the sensing of uranium radiation by Henri Becquerel, Rutherford diverted his attending towards analyzing this radiation. He discovered that by puting U near thin foils one type of radiation emitted by the U was blocked or absorbed by the foil, and he named it ‘alpha ‘ . The 2nd type of radiation passed through the foil, and he gave it the name ‘beta ‘ .

Rutherford ‘s research on radiation provided him with a chair at McGill University in Montreal in 1898. There Rutherford and a co-worker created a new subdivision of natural philosophies called ‘Radioactivity ‘ . They started with the survey of another radioactive component, Thorium, which emitted a gas which he named “ emanation ” which left a solid component which still remained radioactive. Rutherford continued to look into other groups of radioactive elements which led to him in developing the theory of transmutation in 1902 which stated that:

“ Radiation was where the atoms of an component interruption down into atoms of an wholly different component which besides remained radioactive. ”

University of Manchester, 1908 Nobel Prize

In 1907 Rutherford accepted the petition to analyze at the University of Manchester which was followed by him gaining the Nobel Prize for chemical science in 1908 for his work in Montreal. In 1908 with Hans Geiger, a German physicist, Rutherford developed a counter for ionized atoms which became a cosmopolitan tool for mensurating radiation. With this tool, known as the Geiger counter, Rutherford and Thomas Royds counted the atoms emitted by Ra ; besides mensurating the entire charge collected and uniting the consequences with the rate of production of He from Ra. With this information and Bertram Borden Boltwood ‘s aid they calculated the exact value of Avogadro ‘s figure.

The Gold Foil Experiment

In 1909 Rutherford made his greatest part to science with his gold foil experiment. This experiment was carried out by firing alpha atoms through thin gold foil. The consequences were that most of the alpha atoms passed through the gold foil with some being mildly deflected but surprisingly some atoms bounced back to the atom beginning. In 1911 Rutherford came to the decision that the atom was largely empty infinite with a dense positively charged nucleus called the karyon. This theory of atomic construction is known as the Planetary or Rutherford Atomic Model.

Further Work

In 1919 Rutherford examined the hit of alpha atoms with gases bring forthing the first unreal dislocation of an component when he found that when an alpha atom collided with a N atom its protons were removed.

In 1920 Rutherford besides predicted the being of the neutron which was shortly discovered with the aid of Chadwick in 1932, bespeaking that the karyon was composed of protons and neutrons.

From 1933 until his decease Rutherford became president of the Academic Assistance Council which was an administration designed to help fellow scientists who had fled Nazi Germany.

Rutherford ‘s Contribution to the Structure of the Atom

The Plum Pudding ModelRutherford is good known for his “ gilded foil experiment ” conducted in 1909 at the University of Manchester. This experiment led to the find that most of an atom ‘s mass is located in a dense nucleus called the karyon.

The antecedently accepted theoretical account to Rutherford ‘s was the “ plum pudding theoretical account ” by J.J Thompson. His theoretical account falsely showed that negatively charged negatrons of an atom were “ drifting in a sea of positive charge. ”

Gold Foil Experiment apparatus

Rutherford ‘s Atomic Model The gold foil experiment involved a series of trials where positively charged alpha atoms were shot at a really thin bed of foil with sensing screens of Zn sulfide. If J.J. Thompsons theoretical account was right all the alpha atoms would hold passed through the foil with no immense warps. However about one in eight 1000s alpha atoms were deflected at big angles and some even rebounded towards the alpha atom emitter. Rutherford described the consequence as the most unbelievable event of his life stating it was:

“ as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you. ”

These consequences proved that the alpha atoms had collided into dense positively charged concentrations. In 1911 Rutherford proposed his ain theoretical account of the atom where the full atom ‘s positive charge was concentrated into a dense nucleus which was ten thousand times smaller than the full atom with the remainder being empty infinite with negatrons revolving the karyon like planets orbit the Sun.

Rutherford ‘s Model: Discussion


Rutherford ‘s Atomic Model was “ province of the art ” for merely three old ages as it was non wholly right. The major defect in his theoretical account was explicating how negatrons orbited the karyon.

Negatively charged electronFirstly, harmonizing to his theoretical account which was based on the solar system when the Sun is orbited by the planets, the atom ‘s negatively charged negatrons orbited at high velocities around the karyon which was positively charged. The defect here was that, foremost, the constituents of an atom are highly little and the Sun and planets were composed of highly big multitudes. This meant that Newtonian Torahs of gesture did non use to the gesture of the highly little atom.

Positively charged nucleusSecondly, the Sun and planets are non charged like protons and negatrons are. Third, harmonizing to Maxwell ‘s electromagnetic theory, when a charged atom ( in this instance the negatron ) revolves in a field of force ( like the karyon ‘s ) it loses energy as radiation. This loss of energy as radiation would bit by bit decelerate down the negatron undertaking the length of its orbit which would ensue in the negatron finally fall ining into the karyon in a deliberate 10-8 seconds. However this does non happen to the atom and Rutherford ‘s Atomic Model could non explicate how the atom did non prostration consequently. Another defect in Rutherford ‘s theoretical account was that it did non explicate how the theory of the weight of an atom did non use to isotopes. This was due to Rutherford ‘s theoretical account non including the neutron that he had predicted but did non happen.


Rutherford ‘s research impacted the scientific community in several ways. First, his find of the karyon provided greater apprehension of the phenomena of atoms. Rutherford was besides one of the cardinal people involved in making another subdivision of natural philosophies called “ Radioactivity ” . He was responsible for the find of Alpha radiation and helped to make the Geiger counter which greatly benefited the scientific community. Rutherford was besides the first to propose and foretell the being of the neutron and due to his research Chadwick in 1932 verified the being of the neutron. This helped to explicate the altering weight of an atom in isotopes and therefore the agreement of some elements of the periodic tabular array. Rutherford ‘s find led to the apprehension that the revolving negatrons determined the responsiveness of atom.

Another important impact was its part to the development of the first atomic arms of the Manhattan Project during the old ages 1941 to 1946.


The restriction of engineering at the clip impaired some of Rutherford ‘s concluding decisions. Without advanced equipment to observe alpha atoms, Rutherford could non accurately province the exact ratio of reflected alpha atoms in his gold foil experiment. Rutherford besides did non hold entree to some of today ‘s engineerings such as the scanning tunnel microscope which would hold made more dependable and valid his experiments by supplying farther grounds to explicate why the alpha atoms had been deflected. This could hold perchance led him towards the find of the sub atomic atom of the neutron. A basic restriction was that in utilizing the sun/ planets analogy Rutherford and all scientists at the clip were non cognizant of the Torahs of quantum natural philosophies and how they differ from Newtonian natural philosophies.


Rutherford ‘s theoretical account of the atom is one of the most important developments in the theory of atomic construction. The theoretical account explained the presence of a heavy positive nucleus which disproved the old “ plum pudding theoretical account. ” Without this major development the betterment of the theoretical account by Niels Bohr ( explicating how negatrons are arranged in shells and hence supplying some information on the chemical behavior of some atoms ) would evidently non hold been discovered. Rutherford ‘s atomic theory and research was besides instrumental in the find of the neutron by Chadwick two decennaries subsequently.