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Question & Answer:

  • Describe the makeup of the two simplest atoms, hydrogen (atomic number 1) and helium (atomic number 2).
  • 2.2 How much of the mass and how much of the volume of an atom are in the nucleus?
  • What is the ratio of protons to electrons in an atom, and what is the net electric charge of an atom?
  • How is the atomic number of an atom determined?
  • How is the atomic weight (mass number) of an atom determined?
  • What is an isotope?
  • There are three types of oxygen—160, 170, and 180. What are these varieties called?
  • Hydrogen has three isotopes—1H, 2H, and 3H. How do they differ?
  • Uranium 238 (238U), the heaviest naturally occurring element, has an atomic number of 92. How many protons, neutrons, and electrons does it have?
  • Uranium has another isotope with an atomic weight of 235 (235U). How many protons, neutrons, and electrons does it have?
  • Some isotopes undergo radioactive decay and are called radioactive isotopes. For example, 238U (uranium) decays to 206Pb (lead). How does this happen?
  • The process described in Problem 2.11 is a nuclear reaction because it involves changes in the nucleus. Is it nuclear fusion or nuclear fission?
  • What are the differences in the two nuclear processes, fission and fusion?
  • What is a neutron?
  • What is the significance of Einstein’s equation, E = mc2?
  • Explain the statement, “Energy and mass are two aspects of the same thing.”
  • When four hydrogen nuclei, each composed of one proton, join to make one helium nucleus of two protons and two neutrons (as in Problem 2.13 above), the mass of the helium nucleus is calculated to be less than the mass of the original four protons, by the amount of 0.0029 mass units. What is the significance of such a mass “loss”?
  • How are elements probably formed?
  • What is the source of the sun’s energy?
  • What is an ion?