# CH 4 HW PART 2.pdf - CH 4 HW PART 2 Due 11:59pm on Sunday...

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CH 4 HW PART 2 Due: 11:59pm on Sunday, September 24, 2017 To understand how points are awarded, read the Grading Policy for this assignment. Animation—Rutherford’s Experiment: Nuclear Atoms Watch the animation and study Rutherford’s nuclear atom model. In 1909, Ernest Rutherford performed an experiment to explore the atomic structure. In his experiment, he projected high-speed positively charged particles onto a thin gold foil. He found that all particles did not follow the same path. Many particles passed through the foil without any scattering, implying that most of the space in an atom is empty. Some particles were scattered at a large angle, and very few of them scattered back in the direction from which they had come. Based on these observations, Rutherford proposed an atomic model, which is known as Rutherford’s atomic model. Part A - Conclusions from Rutherford’s experiment Watch the animation depicting Rutherford’s experiment and choose which of the following conclusions are correct. Check all that apply. Hint 1. Rutherford’s experiment In Rutherford’s experiment, he bombarded positively charged particle from a radioactive source onto thin gold foil. The foil was surrounded by a sheet of fluorescent material (zinc sulfide ). The sheet lit up when it was hit with particles. The image below shows the scattering of particles. The circular green spots on the fluorescent screen are formed when the particles hit the screen. By looking at the number of particles that scattered at different angles from the gold foil, Rutherford proposed an atomic model, which is known as Rutherford’s atomic model. The image given below explains the molecular view of the scattering of particles from the gold foil. Typesetting math: 100%
Hint 2. Identify the observations of Rutherford’s experiment Study Rutherford’s model explaining the scattering of a particles from the gold nucleus and choose which of the following observations are correct. Check all that apply. Hint 3. Conclusions from Rutherford's Experiment Using the observations of Rutherford’s experiment, you can draw the following conclusions based on the properties of particles and the nature of charged particles: 1. Most of the particles pass straight through the gold foil without any deflection. This implies that an atom consists largely of empty space. 2. Some of the particles are scattered, at both small and large angles, which implies that there is a core of positive charge in an atom that repels the positively charged particles. 3. Very few particles return in the direction from which they came after striking the gold foil. This implies that there is an area in the atom, the nucleus, that is very dense and does not allow the particles to pass through it. The mass of the atom is centered in one location at this nucleus. Correct