1. Towards the 19th century, Joseph John Thomson was able to discover that atoms have negatively charged particles, which he called It led him to propose a new model for the atom, which he called the model of the atom.
Answer:
J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup."
2. In the plum pudding model of the atom, negatively charged electrons were embedded in a cloud of charge.
Answer:
Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup." Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom.
3. Ernest Rutherford and his team performed the experiment to test the model of Joseph John Thomson. They fired alpha particles on a thin sheet of gold foil.
Answer:
In Rutherford's gold foil experiment, a beam of α particles that was shot at a thin sheet of gold foil. Most of the α particles passed straight through the gold foil, but a small number were deflected slightly, and an even smaller fraction were deflected more than 9 0 ∘ 90^{\circ} 90∘ from their path.
4. Observations in the gold foil experiment are the following: Most of the alpha rays just through the gold foll. A small portion of the alpha particles was deflected. . An even smaller portion of the alpha particles bounced right back,
Answer:
Rutherford considered these observations and he concluded: The fact that most alpha particles went straight through the foil is evidence for the atom being mostly empty space. A small number of alpha particles being deflected at large angles suggested that there is a concentration of positive charge in the atom.
5. These observations suggested a different structure of the atom where all the positive charge and nearly all the mose of the atom were concentrated in a very tiny region called the at the center of the atom.
Answer:
The nucleus was postulated as small and dense to account for the scattering of alpha particles from thin gold foil, as observed in a series of experiments performed by undergraduate Ernest Marsden under the direction of Rutherford and German physicist Hans Geiger in 1909. A radioactive source emitting alpha particles (i.e., positively charged particles, identical to the helium atom nucleus and 7,000 times more massive than electrons) was enclosed within a protective lead shield. The radiation was focused into a narrow beam after passing through a slit in a lead screen. A thin section of gold foil was placed in front of the slit, and a screen coated with zinc sulfide to render it fluorescent served as a counter to detect alpha particles. As each alpha particle struck the fluorescent screen, it produced a burst of light called a scintillation, which was visible through a viewing microscope attached to the back of the screen. The screen itself was movable, allowing Rutherford and his associates to determine whether or not any alpha particles were being deflected by the gold foil.
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