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Questions and Answers
What is the primary theory of atomic structure that states that atoms of different elements combine in simple whole-number ratios?
What discovery did J.J. Thomson make in 1897 using a cathode ray tube?
What is defined as the emission of a photon when an electron transitions to a lower energy level?
Which of the following best describes isotopes?
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According to the correspondence principle, what happens as the quantum number increases?
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Which of the following statements is a component of atomic theory?
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What would happen if there is no voltage difference (ΔV = 0) in the Thomson experiment?
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Who proposed the existence of isotopes and received the Nobel Prize for this work?
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What happens to electrons as they travel through a tube containing gas?
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Under what condition can no current be measured in a vacuum tube?
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What is observed when the accelerating voltage (VA) reaches multiples of approximately 4.9V in the Franck-Hertz experiment with mercury gas?
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What does the drop in current at specific voltages indicate about the energy levels of Hg atoms?
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What effect do elastic collisions have on the movement of electrons in a gas-filled tube?
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Which of the following statements is true regarding the behavior of electrons at the collector?
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What is the role of retarding voltage (Vr) in a gas-filled tube experiment?
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Why is the idea that atoms are indivisible incorrect based on the given content?
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Study Notes
Atomic Structure
- An atom is composed of a positively charged nucleus and negatively charged electrons
- Atoms are mostly empty space
Discovery of the Electron
- J.J. Thomson discovered the electron using a cathode ray tube in 1897
- Cathode rays are negatively charged particles
- Thomson deflected the cathode rays using an electric field
- By measuring the deflection, Thomson was able to determine the charge-to-mass ratio of the electron
- The charge-to-mass ratio of the electron is very large, indicating that the electron is a very light particle
- Thomson's discovery showed that atoms are not indivisible
Franck-Hertz Experiment
- The Franck-Hertz experiment provided evidence for the quantization of energy levels in atoms by demonstrating that electrons can only lose energy in discrete amounts
- The experiment involved passing electrons through a gas of mercury atoms and measuring the current as a function of the accelerating voltage
- At specific voltages, the current dropped because electrons were undergoing inelastic collisions with mercury atoms
- The energy lost by the electrons was transferred to the internal energy of the mercury atoms, causing the mercury atoms to become excited
- The experiment demonstrated that electrons could only lose energy in discrete amounts, corresponding to the energy levels of mercury atoms
- The spacing between the energy levels of the mercury atoms was determined to be 4.9 eV, consistent with the theoretical prediction of quantum mechanics
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Description
Explore the fundamental concepts of atomic structure including the composition of atoms, the discovery of the electron by J.J. Thomson, and the Franck-Hertz experiment's insights into energy quantization. This quiz covers essential principles and historical experiments that shaped our understanding of atomic theory.
