Atoms Thomson model

The first observation made with this apparatus was that apparently all the alpha particles passed through the foil undeflected. Let us see if this result is consistent with the model of the atom proposed by Thomson. You will recall that Thomson s picture of the atom assumed that the positive charge is distributed evenly throughout the entire volume of the atom with the negative electrons embedded in il. Since the electrons weigh so little, the positive part accounts for nearly all of the mass of the atom. Thus the Thomson model pictures the atom as a body of uniform density. 

Thermal equilibrium, 56 Thermite reaction, 122 Thermometers, 56 Thiosulfate ion, 362 Third-row elements, 101 compounds, 102 physical properties, 102 properties, table, 101 Third row of the periodic table, 364 Thomson, J. J., 244 Thomson model of atom, 244 Thorium... 

Electrons. If the discovery of isotopes threatened ro undermine the periodic system, the discovery of the electron explained many of the periodic properties on which the table was based. J. J. Thomson attempted to explain the periodic system by postulating rings of electrons embedded in the positive charge that made up his phim pudding model of the atom. Thomson s model was quickly superseded by more sophisticated and elaborate mod-... 

Thomson s plum-pudding model of the atom. Thomson proposed that the atom might be made of thousands of tiny, negatively charged particles swarming within a cloud of positive charge, much like plums and raisins in an old-fashioned Christmas plum pudding. 

If the Thomson model of the atom were correct, any a-particles passing through the foil would have been deflected by very small angles. Quite unexpectedly, nearly all of the a-particles passed through the foil with little or no deflection. A few, however, were... 

When Rutherford s coworkers bombarded gold foil with a particles, they obtained results that overturned the existing (Thomson) model of the atom. Explain. 

Describe how the Rutherford a-particle scattering experiment (a) overturned the Thomson model of the atom and (b) led to a conflict with the predictions of classical physics. 

TheoreticThomson model (a mix of peirticles with positive md negative charges), B— the Rutherford model (a positive nucleus surroimded by electrons), C—the Bohr model (stating that electrons follow defined orbits around a nucleus), [Pg.14]

Einstein was not the only one to find Planck s concept useful. In the laboratory of J. J. Thomson, Niels Bohr was in conflict with his mentor over the proper model for an atom. Thomson adhered to his plum pudding model, and Bohr preferred the planetary model of Rutherford. Finally Thomson suggested that Bohr work with Rutherford (who by this time had relocated in Manchester), and Bohr obliged. 

Thomson model of the atom. In this early model of the atom, negative particles (electrons) were thought to be embedded In a positively charged sphere. It Is sometimes called the plum pudding model. 

In the Thomson model of the atom, the electrons are negatively charged particles embedded in the positively charged atomic sphere (see Figure 5.4). A neutral atom could become an ion by gaining or losing electrons. 

Rutherford gold foil experiment modified the Thomson model to a nuclear model of the atom ... 

Thomson model of the atom Thomson asserted that atoms are not indivisible but are composed of smaller parts they contain both positively and negatively charged particles—protons as well as electrons. [5.6] titration The process of measuring the volume of one... 

The first detailed model of the atom, proposed by J. J. Thomson in 1898, was based upon the expectation that the atom was a sphere of positive electricity in which electrons were embedded like plums in a pudding. This picture of the atom was not particularly satisfying because it was not useful in predicting or explaining the chemical properties of the atom. Finally, in 1911, a series of experiments performed in the McGill University laboratory of Ernest Rutherford showed that Thomson s picture of the atom had to be abandoned. 

Mendeleev s reluctance toward reduction was not widely shared. One of the codiscoverers of the periodic system, the German Lothar Meyer, accepted the possibility of primary matter and supported Prouf s hypothesis. He was also happy to draw curves through numerical data, including his famous plot of atomic volumes that showed such remarkable periodicity that it helped in the acceptance of the periodic system. Nonetheless, prior to Thomson s discovery of the electron, no accepted model of atomic substructure existed to explain the periodic system, and the matter was still very much in dispute. 

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