Rutherford, Ernest, atomic structure

Ernest Rutherfords proposed atomic structure added to the problems posed to nineteenth century physics by the ultraviolet catastrophe and the photoelectric effect. Rutherfords atom had a negatively charged electron circling a positively charged nucleus. The physics of the day predicted that the atom would emit radiation, causing the electron to lose energy and spiral down into the nucleus. Theory predicted that Rutherfords atom could not exist. Clearly, science needed new ideas to explain these three anomalies. 

The last big problem facing early twentieth century physics was Ernest Rutherford s atomic structure. Physicists knew that Rutherford s atom could not exist, but no one could come up with anything better. The man who would resolve this conundrum showed up at Manchester, England, in 1912 to work for Rutherford. Rutherford himself had worked for J.J. Thomson and had disproved Thomson s plum pudding structure of the atom. Now, the new man in Manchester, Niels Bohr, was about to do the same thing to Rutherford. By the end of his career, Bohr would have contributed as much as anyone to understanding Feynman s little particles. Science is a meritocracy. Poor kids can excel and get ahead in the world of science just as easily as the well-heeled. For example. 

Ernest Rutherford studied atomic structure in 1910-1911 by firing a beam of alpha particles at thin layers of gold leaf. According to Thomson s model, the path of an alpha particle should be deflected only slightly if it struck an atom, but Rutherford observed some alpha particles bouncing almost backwards, suggesting that nearly all the mass of an atom is contained in a small positively charged nucleus. 

By the late 1800s most scientists were convinced that matter was composed of atoms. However, they did not know the basic structure of the atom. Were atoms solid spheres like billiard balls, or were they soft and pliable like blueberry muffins In 1909 the internal structure of the atom was studied by Ernest Rutherford (1871-1937). Rutherford examined atomic structure by directing small particles, called alpha particles, at a thin sheet of gold foil (Figure 1-10). If the atoms in the foil were like soft blueberry muffins, an idea favored by Rutherford, the small particles should shoot right through the gold foil. 

The third experiment that is crucial to understanding atomic structure was carried out by Ernest Rutherford in 1911 and is known as Rutherford s experiment. It consists of bombarding a thin metal foil with alpha (a) particles. Thin foils of metals, especially gold, can be made so thin that the thickness of the foil represents only a few atomic diameters. The experiment is shown diagrammatically in Figure 1.2. 

The exploration of atomic structure began in 1911, when Ernest Rutherford, a New Zealander who worked in Canada and England, discovered that atoms had a dense central nucleus that contained positively charged particles, which he named protons. (See Table 3-1.) it was soon established that each chemical element was characterized by a specific number of protons in each atom. A hydrogen atom has 1 proton, helium has 2, lithium has 3, and so forth through the periodic table. The atomic number is the number of protons for each element. 

MOSLEY. HENRY 11887-1915). A British chemist who studied under Ernest Rutherford and brilliantly developed the application of X-ray spectra to the study of atomic structure his discoveries resulted in a more accurate positioning of elements in the periodic tahle hy closer determination of atomic numbers. Tragically for the development of seienee. Moscly was killed in action al Gallipoli in 1915. 

RUTHERFORD, ERNEST (1871-1937). Rutherford was a British physicist who was bom in the South Island of New Zealand and is famous for his pioneering work in nuclear physics and for his theory of the structure of the atom. 

Think about the consequences of Thomson s cathode-ray experiments. Because matter is electrically neutral overall, the fact that the atoms in an electrode can give off negatively charged particles (electrons) must mean that those same atoms also contain positively charged particles. The search for those positively charged particles and for an overall picture of atomic structure led to a landmark experiment published in 1911 by the New Zealand physicist Ernest Rutherford (1871-1937). 

This was initiated by the first description of the atom structure in 1913 by Ernest Rutherford, a British scientist and Niels Bohr, a Danish scientist. Then came the discovery of the neutron in 1932 by James Chadwick (a British student of Rutherford), the discovery of artificial radioactivity by Irene and Frederic Joliot Curie (Nobel Prize in chemistry in 1935) and finally the discovery of fission in 1938 by Lise Meitner, Otto Hahn and Fritz Strassman (German scientists) which brought Hahn the Nobel Prize for physics in 1944. 

To learn more about the discovery of atomic structure, visit the Chemistry Web site at chemistrymc.com Activity Research Ernest Rutherford s work. Write a newspaper article announcing his model of the atom. 

Soon after Thomson developed his model, tremendous insight into atomic structure was provided by one of Thomson s former students, Ernest Rutherford (1871-1937), who was the outstanding experimental physicist of his time. 

Ernest Rutherford was one of the giants in the development of our understanding of atomic structure. While working with J. J. Thomson at Cambridge University, he discovered a and /3 radiation. He spent the years 1899-1907 at McGill University in Canada where he proved the nature of these two radiations, for which he received the Nobel Prize in chemistry in 1908. 

In 1911, a new idea about atomic structure was described by Ernest Rutherford. In his famous scattering experiments, Ernest Rutherford discovered that atoms consisted of a major part that contained nothing and that almost all the mass of the atom was concentrated in a very small core. 

Near the turn of the 20" century, French scientists discovered radioactivity, the emission of particles and/or radiation from atoms of certain elements. Just a few years later, in 1910, the New Zealand-born physicist Ernest Rutherford (1871-1937) used one type of radioactive particle in a series of experiments that solved this dilemma of atomic structure. 

Several major discoveries at the turn of the 20 century ied to our current model of atomic structure. Cathode rays were shown to consist of negative particles (electrons) that exist in ail matter. J. J. Thomson measured their mass/charge ratio and con-ciuded that they are much smalier and iighter than atoms. Robert Miliikan determined the charge of the electron, which he combined with other data to calculate its mass. Ernest Rutherford proposed that atoms consist of a tiny, massive, positive nucleus surrounded by electrons. 

In 1911, the British physicist and Nobel laureate Ernest Rutherford (1871-1937) published the article The Scattering of Alpha and Beta Particles by Matter and the Structure of the Atom in Philosophical Magazine. In this article, Rutherford reported the results of an experiment that demonstrated that the protons and electrons in atoms are not distributed homogeneously. Instead, the protons are concentrated in a relatively tiny region Rutherford called the nucleus (from the Latin, meaning kernel ). The electrons are extranuclear electrons are located in a relatively much larger volume of space surrounding the nucleus. Rutherford s discovery of the nucleus was immediately accepted within the scientific community. However, the relationship, if any, between atomic structure and properties was still unclear. 

Joseph John ( JJ ) Thomson (left) and Ernest Rutherford. Both were awarded Nobel Prizes, Thomson In 1906 (for his work on atomic structure) and Rutherford In 1908 (for his work on radioactivity). Much to Thomson s delight, his son, George, also won the Nobel Prize for Physics (In 1937). 

III) Niels Bohr and (Iv) Ernest Rutherford made major contributions to our understanding of atomic structure. 

Describe the contributions of the following scientists to our knowledge of atomic structure J. J. Thomson, R. A. Millikan, Ernest Rutherford, James Chadwick. 

Rutherford, Ernest (1st Baron Rutherford of Nelson) (1871-1937) New Zealand-born British pioneer of subatomic particle physics who proposed the nuclear structure of the atom. He studied the radioactive disintegration of elements and correctly predicted the existence of the neutron. Rutherford won the Nobel Prize in chemistry in 1908. 

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