CR Chemistry A Module 2 Lesson 1
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Questions and Answers

What issue was identified with the early atomic model regarding atomic weight and atomic number?

  • The atomic number was much higher than atomic weight.
  • The atomic number was usually about half of the atomic weight. (correct)
  • The atomic weight did not account for neutrons.
  • The atomic weight was solely based on the number of neutrons.
  • What did Ernest Rutherford propose to explain the existence of neutral particles in the nucleus?

  • That the existence of neutrons was unnecessary.
  • That neutral particles were not present at all.
  • That they were combinations of protons and electrons. (correct)
  • That these particles were electrons combining with neutrons.
  • Which experiment led to the identification of the neutron?

  • Investigation of alpha particles in a magnetic field.
  • Bombardment of carbon with alpha particles.
  • Bombardment of beryllium with alpha particles. (correct)
  • Direct measurement of electron velocity in vacuo.
  • How do neutrons contribute to the process of nuclear fission?

    <p>They initiate the chain reaction by colliding with large atoms.</p> Signup and view all the answers

    What was a major application of neutrons mentioned in the content?

    <p>They help in the nuclear fission process to produce new isotopes.</p> Signup and view all the answers

    What is one reason describing a sports car is easier than describing an atom?

    <p>Atoms are too small to observe directly.</p> Signup and view all the answers

    How did J.J. Thomson contribute to the understanding of the electron?

    <p>He showed that cathode rays are negatively charged particles.</p> Signup and view all the answers

    What analogy is used to describe the process of scientific research?

    <p>Solving a crime.</p> Signup and view all the answers

    What is often a challenge when making new scientific discoveries?

    <p>Absence of a shared language to describe new findings.</p> Signup and view all the answers

    What can be inferred about the relationship between different scientific findings?

    <p>Research builds upon previous findings.</p> Signup and view all the answers

    What happens to an atom when it loses electrons?

    <p>It becomes positively charged.</p> Signup and view all the answers

    Why might research findings sometimes seem unclear?

    <p>Some pieces of information may be missing.</p> Signup and view all the answers

    What did Millikan's experiment demonstrate about electrical charge?

    <p>Charge exists in whole-number multiples of a basic unit.</p> Signup and view all the answers

    What particle remains after the electron is removed from a hydrogen atom?

    <p>Proton</p> Signup and view all the answers

    What was Eugene Goldstein's significant discovery about particles?

    <p>Canal rays are composed of positively charged particles.</p> Signup and view all the answers

    What did J.J. Thomson conclude about the cathode ray after his experiments?

    <p>Cathode rays are streams of negatively charged particles.</p> Signup and view all the answers

    How did Thomson prove that cathode rays had mass?

    <p>By using a paddle wheel that rotated when rays passed.</p> Signup and view all the answers

    What did researchers find regarding the mass of electrons in relation to protons?

    <p>One proton weighs approximately 1837 electrons.</p> Signup and view all the answers

    What does Dalton’s atomic theory state about atoms?

    <p>Atoms are indivisible.</p> Signup and view all the answers

    What are canal rays composed of, as discovered by Goldstein?

    <p>Positively charged particles.</p> Signup and view all the answers

    What principle underlies the interaction of charged plates with cathode rays?

    <p>Opposites attract and likes repel.</p> Signup and view all the answers

    It is easier to describe a sports car than to describe an atom.

    <p>True</p> Signup and view all the answers

    J.J. Thomson discovered the proton through his experiments with cathode rays.

    <p>False</p> Signup and view all the answers

    An electric current passed through a cathode ray tube emits positively charged particles.

    <p>False</p> Signup and view all the answers

    The process of scientific research often involves connecting various findings like puzzle pieces.

    <p>True</p> Signup and view all the answers

    Atoms can be directly observed and studied in detail by scientists.

    <p>False</p> Signup and view all the answers

    A hydrogen atom has no protons when its electron is removed.

    <p>False</p> Signup and view all the answers

    Eugene Goldstein discovered negatively charged particles traveling in opposite directions in a cathode ray tube.

    <p>False</p> Signup and view all the answers

    The mass of the proton is approximately 1840 times greater than that of the electron.

    <p>True</p> Signup and view all the answers

    J.J. Thomson used a cathode ray tube to show that cathode rays are streams of positively charged particles.

    <p>False</p> Signup and view all the answers

    The discovery of the neutron involved direct observation of this neutral particle.

    <p>False</p> Signup and view all the answers

    Study Notes

    Atomic Structure and Discovery

    • Describing a sports car is straightforward due to visibility and shared language, unlike atomic particles.
    • Atoms cannot be directly observed, complicating descriptions and discoveries in atomic science.
    • Scientific research often builds on previous findings, connecting pieces of information like a puzzle.

    Electron Discovery

    • J.J. Thomson discovered electrons in 1897 using a cathode ray tube, demonstrating they are negatively charged particles.
    • Cathode rays cast shadows and could rotate a paddle wheel, indicating the presence of particles with mass.
    • Thomson's experiments showed that cathode rays are deflected by magnetic fields, confirming the presence of negatively charged electrons.
    • The charge-to-mass ratio of electrons determined by Thomson was 1.8 × 10⁸ Coulombs/gram, consistent across different gases.

    Proton Discovery

    • Eugene Goldstein discovered canal rays in 1886, indicative of positively charged particles, later identified as protons.
    • Protons are present in all atoms, possessing a mass approximately 1840 times greater than that of electrons.

    Neutron Discovery

    • The concept of an uncharged particle in the nucleus arose when atomic mass did not align with the number of protons.
    • Rutherford proposed that electrically neutral particles existed alongside protons.
    • In 1930, experiments by German researchers and later by James Chadwick confirmed the existence of neutrons, which share a mass similar to protons but carry no charge.
    • Chadwick's work earned him the Nobel Prize in Physics in 1935.

    Applications of Neutrons

    • Neutrons are critical in nuclear fission, enabling the formation of new isotopes by colliding with large atoms like uranium.
    • Neutrons initiate chain reactions in nuclear reactors, generating heat to produce steam and drive turbines for electricity generation.

    Atomic Structure and Discovery

    • Describing a sports car is straightforward due to visibility and shared language, unlike atomic particles.
    • Atoms cannot be directly observed, complicating descriptions and discoveries in atomic science.
    • Scientific research often builds on previous findings, connecting pieces of information like a puzzle.

    Electron Discovery

    • J.J. Thomson discovered electrons in 1897 using a cathode ray tube, demonstrating they are negatively charged particles.
    • Cathode rays cast shadows and could rotate a paddle wheel, indicating the presence of particles with mass.
    • Thomson's experiments showed that cathode rays are deflected by magnetic fields, confirming the presence of negatively charged electrons.
    • The charge-to-mass ratio of electrons determined by Thomson was 1.8 × 10⁸ Coulombs/gram, consistent across different gases.

    Proton Discovery

    • Eugene Goldstein discovered canal rays in 1886, indicative of positively charged particles, later identified as protons.
    • Protons are present in all atoms, possessing a mass approximately 1840 times greater than that of electrons.

    Neutron Discovery

    • The concept of an uncharged particle in the nucleus arose when atomic mass did not align with the number of protons.
    • Rutherford proposed that electrically neutral particles existed alongside protons.
    • In 1930, experiments by German researchers and later by James Chadwick confirmed the existence of neutrons, which share a mass similar to protons but carry no charge.
    • Chadwick's work earned him the Nobel Prize in Physics in 1935.

    Applications of Neutrons

    • Neutrons are critical in nuclear fission, enabling the formation of new isotopes by colliding with large atoms like uranium.
    • Neutrons initiate chain reactions in nuclear reactors, generating heat to produce steam and drive turbines for electricity generation.

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    Description

    Explore the fascinating world of atomic structure and the key discoveries that shaped modern physics. This quiz covers the contributions of scientists like J.J. Thomson and Eugene Goldstein in identifying electrons and protons. Test your knowledge on the principles of atomic particles and their properties.

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