Atoms gold foil experiment, Rutherford

From his gold-foil experiments, Rutherford realized that the protons must be contained in a small, positively charged region at the center of the atom, which he called the nucleus. He proposed that the electrons in the atom occupy the space surrounding the nucleus through which most of the particles traveled undisturbed. Only the particles that came near this dense, positive center were deflected. If an atom were the size of a football stadium, the nucleus would be about the size of a golf ball placed in the center of the field. 

As you may recall from earlier studies, the flaw lay in Thomson s model. In 1911, Rutherford published the results of the now-famous gold-foil experiment, shown in Figure 3.4. On the basis of this experiment, Rutherford suggested that the deflections he and his students observed were caused by an encounter between an alpha particle and an intense electric field at the centre of the atom. 

Around 1910, a more accurate picture of the atom came to one of Thomsons former students, the New Zealand physicist Ernest Rutherford (1871—1937). Rutherford oversaw the now-famous gold-foil experiment, which was the first experiment to show that the atom is mostly empty space and that most of its mass is concentrated in a tiny central core called the atomic nucleus. 

Rutherford s gold-foil experiment. A beam of positively charged alpha particles was directed at a piece of gold foil. Most of the particles passed through the foil undeflected, but some were deflected. This result implied that each gold atom was mostly empty space with a concentration of mass at its center—the atomic nucleus. 

Rutherford s interpretation of the results from his gold-foil experiment. Most alpha particles passed through the empty space of the gold atoms undeflected, but a few were deflected by an atomic nucleus. 

Ernest Rutherford a, (3, and -y emissions gold-foil experiment nuclear model of the atom Determined the nature of radioactive particles. His gold-foil experiment established the presence of a positively charged nucleus and that the atom is mostly empty space. 

The correct answer is (E). Rutherford, based on the results of his gold-foil experiment, developed a model of the atom that included a positively charged dense core (the nucleus). 

The History of the Atom Dalton s Atomic Theory Rutherford s Gold Foil Experiment Subatomic Particles Isotopes... 

T, T, CE Rutherford s gold foil experiment showed that alpha particles can pass through a sheet of gold foil, proving that the atom is mainly empty space. 

All the statements are included in the Atomic Theory except for the empty space concept of the atom. This was concluded by Rutherford in his gold foil experiment. 

Soon after the atomic theory was widely accepted by scientists, they began constructing models of atoms. Scientists used the information that they had about atoms to build these models. They knew, for example, that an atom has a densely packed nucleus that is positively charged. This conclusion was the only way to explain the data from Rutherford s gold foil experiments. 

How did the results of the gold foil experiment lead Rutherford to recognize the existence of atomic nuclei ... 

In 1911, Ernest Rutherford s famous gold-foil experiment determined the distribution of charge and mass in an atom. Rutherford s results showed that all of an atom s positive charge and almost all of its mass are contained in an extremely small nucleus. 

Rutherford concluded that the plum pudding model was incorrect because it could not explain the results of the gold foil experiment. He set out to develop a new atomic model based upon his findings. Considering the properties of the alpha particles and the electrons, and the frequency of the deflections, he calculated that an atom consisted mostly of empty space through which the electrons move. He also concluded that there was a tiny, dense region, which he called the nucleus, centrally located within the atom that contained all of an atom s positive charge and virtually all of its mass. Because the nucleus occupies such a small space and contains most of an atom s mass, it is incredibly dense. Just how dense If a nucleus were the size of the dot in the exclamation point at the end of this sentence, its mass would be approximately as much as that of 70 automobiles ... 

Rutherford s nuclear model of the atom explains the results of the gold foil experiment. Most alpha particles pass straight through, being only slightly deflected by electrons, if at all. The strong force of repulsion between the positive nucleus and the positive alpha particles causes the large deflections. 

Why are the results of Rutherford s gold foil experiment more consistent with a nuclear model of the atom than with the chocolate-chip cookie dough model ... 

Ernest Marsden stndied at the University of Manchester under Ernest Rutherford and Eians Geiger. Although a physicist, he would help elucidate something of value to all chemists the internal structure of the atom. This was accomplished by observing the path of a-particles in Rutherford s famous gold foil experiment, in which it was really the human eye, pressed to a short-focus telescope for hours on end in a thoroughly darkened room, that was the detector. 

Not long after Rutherford s gold foil experiment, the English scientist Henry Moseley (1887-1915) discovered that atoms of each element contain a unique positive charge in their nuclei. Thus, the number of protons in an atom identifies it as an atom of a particular element. The number of protons in an atom is referred to as the atomic number. 

Experiments were under way to understand how electricity and matter interact when the discoveries of x-rays and radioactivity were announced. Scientists trying to understand this new phenomena radioactivity experimented day and night. Ernest Rutherford was one of the many. He tried to understand the nature of radioactivity and classified it into three basic types. While trying to find out more about radioactivity, he conducted his gold foil experiment that ultimately provided greater insight into the subatomic nature of the atom by discovering the nucleus. He also identified the proton present in the nucleus. 

FIGURE 3.3 Rutherford s interpretation of the gold foil experiment done by Geiger and Marsden. Each circle represents an atom and the dots represent their nuclei. The gold foil was about 1000 atoms thick. 

Prior to Rutherford s gold-foil experiment, the mass and positively charged particles of an atom were thought to be evenly distributed throughout the volume of the atom, (a) Watch the movie of the Rutherford Experiment (eChapter 2.2), and describe how the experimental results would have been different if the earlier model had been correct, (b) What specific feature of the modern view of atomic structure was illuminated by Rutherford s experiment ... 

Discovery of the Atom s Nucieus Rutherford s gold foil experiment probed atomic structure, and his results led to the nuclear model of fhe atom, which, with minor modifications to accommodate neutrons, is still valid today. In this model, the atom is composed of protons and neutrons—which compose most of the atom s mass and are grouped together in a dense nucleus—and electrons, which compose most of the atom s volume. Protons and neutrons have similar masses (1 amu), while electrons have a much smaller mass (0.00055 amu). Discovery of the Atom s Nucleus We can understand why this is relevant by asking, what if it were otherwise What if matter were not mostly empty space While we cannot know for certain, it seems probable that such matter would not form the diversity of substances required for life—and then, of course, we would not be around to ask the question. 

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