Plum pudding model, of the atom

Figure 1.2 The plum pudding model of the atom consisted of electrons scattered in a sphere of positive charge.

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. 

It was reasoned that if atoms contained negatively charged particles, some balancing positively charged matter must also exist. From this, Thomson put forth what he called a plum-pudding model of the atom, shown in Figure 3-15- Further experimentation, however, soon proved this model to be wrong. 

J. J. Thomson (1856-1940), an English physicist, proposed a plum pudding model of the atom, in which the atom was a diffuse cloud of positive charge (the pudding) negatively charged electrons (the raisins) were embedded randomly in the cloud. 

Joseph John Thomson, often known as J. J. Thomson, was the first to examine this substructure. In the mid-1800s, scientists had studied a form of radiation called "cathode rays" or "electrons" that originated from the negative electrode (cathode) when electrical current was forced through an evacuated tube. Thomson determined in 1897 that electrons have mass, and because many different cathode materials release electrons, Thomson proposed that the electron is a subatomic particle. Thomson s model of the atom was a uniformly positive particle with electrons contained in the interior. This has been called the "plum-pudding" model of the atom where the pudding represents the uniform sphere of positive electricity and the bits of plum represent electrons. For more on Thomson, see http //www.aip.org/historv/electron/iihome.htm. 

The correct answer is (D). Thomson s work with cathode rays led to his eventual discovery of many important properties of the electron and his subsequent development of the plum pudding model of the atom. 

Consider Ernest Rutherford s alpha-particle bombardment experiment illustrated in Figure 2.11. How did the results of this experiment lead Rutherford away from the plum pudding model of the atom to propose the nuclear model of the atom ... 

Thomson proposed that the electrons of an atom were embedded in a positively charged ball of matter. His picture of an atom, which is shown in Figure 7, was named the plum-pudding model because it resembled plum pudding, a dessert consisting of a ball of cake with pieces of fruit in it. Ernest Rutherford, one of Thomson s former students, performed experiments in 1909 that disproved the plum-pudding model of the atom. 

This has been called the "plum-pudding" model of the atom where the pudding represents the uniform sphere of positive electricity and the bits of plum represent electrons. For more on Thomson, see http //www.aip.org/historv/electron/iihome.htm. 

Thomson devised the famous plum pudding model of the atom, in which electrons were compared to negative plums embedded in a positively charged pudding. The idea was wrong, and his successor at Cambridge, Ernest Rutherford, was soon to develop the nuclear model of the atom. 

Figure 4.9 J. J. Thomson s plum pudding model of the atom states that the atom is a uniform, positively charged sphere containing electrons. 

The purpose of this first computer laboratory is to review some of the fundamental concepts from classical physics, to understand what constitutes a solution to a problem in classical physics, and to introduce students to numerical solutions for the Newtonian equations of motion. QuickBASIC programs have been written which use PC graphics to display the trajeaory of an electron in the Thomson plum pudding model of the atom, the Bohr atom, and a classical model for the hydrogen-molecule ion. This early review of classical physics helps students appreciate more fully how fundamentally different quantum theory is. The material in this exercise is frequently used as a leaure demonstration to support a classroom lecture on the precursors to the quantum theory of atomic and molecular structure. 

J. J. Thomson proposes his plum pudding model of the atom, with electrons embedded in a nucleus of positive charges. Japanese physicist Hantaro Nagaoka (1865-1950) proposes a Saturn model of the atom with a central nucleus having a ring of many electrons. 

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