science 13

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  1. model
    a schematic description of a system that accounts for its know properities
  2. nucleus
    the center of an atom containing the protons and nuetrons
  3. atomic number
    the numbers of protons in an atom
  4. mass number
    the sum of neutrons and protons in the nucleus of an atom
  5. isotopes
    atoms with the same number of protons but different numbers of neutrons
  6. element
    a collection of atoms that all have the same number of protons
  7. radioactive isope
    an atom with a nucleus that is not stable
  8. half-life
    the time it takes for halr of the original sample of a radioactive isotope to decay
  9. Order the three constituet parts of the atom IN TERMS OF THEIR MASS FROM LEAST MASSIVE TO MOST MASSIVE.
    electron, protons,neutron
  10. What force keeps the protons and neutrons in the nucleus? What causes this force?
    The strong  nuclear force. it occurs as a result of the fact that protorns and nuetrons exchange pions with one anotheer
  11. What force keeps the electrons orbiting around the nucleus.
    electromagnetic force
  12. What is an atom mostly made of?
    empty space
  13. An atom has a atomic number of 34. How many protons and electrons does it have ? What is its sylmbol?
    Se is the symbol and it has 34 electrons and protrons.
  14. List the number of protons , electron and neutrons  for each of the following atoms.

    56Fe   139La  24Mg  20 Ne
    Fe: 26 protons, 26 electrons, 30 neutrons

    La: 57 protons , 57 electrons, 82 neutrons

    Mg: 12 protons, 12 electrons, 12 neutrons

    Ne: 10 protons , 10 electrons, 10 neutrons
  15. Two atoms are isotopes. the first has 18 prtons and 20 nuetrons. the second has 22 neutrons. how many protons does it have?
    18 protons
  16. which of the following are isotopes?

    112Cd   112Sn  120Xe  124Sn   40Ar    120Sn
    112Sn   and 124Sn  120Sn
  17. what is the largest bhor orbit in a uranium atom and how many electrons are in it.
    5th orbit and 32 electrons
  18. why is the strong force nuclear force such a short ranged force.
    Since pions have a very short lifetime, the strong nuclear force can only act over very tiny distances.
  19. determine the daughter products produced in the beta decay of the 2 radioactive isopes shown below: 1:  98Tc     2:  125I
    • 1:  98Ru        
    • 2:  125Xe
  20. determine the daughter products of these atoms after alpha decay:

    212Bi            2: 224Ra
    • 1:208Ti
    • 2: 220Rn
  21. A radioactive isotope goes through radioactive decay but the isotopes number of protons and neutrons does not change . what kind of radioactivity decay occurred.
    gamma decay
  22. The half-life of the radioactive decay of 226Ra is 1600 years. if a sample of 226Ra originally had a mass of 10 grams how many grams of 226Ra would be left after 3200 years.
    X 2.5 grams
  23. if the life of a man-made isotope 11C is 2o minutes.  If a scientist makes I gram of 11C how much will be left in 1 hour.
    0.125 grams
  24. why is radioactive dating inrelable in most situations
    with radioactive dating you have to make assumptions.
  25. List the 3 types of radioactive particles discussed in this moduale in order of their ability to travel through matter. start with the weakest one.
    alpha particles pass through the least amount of matter before stopping , beta particles are next, gamma rays pass through the most matter before stopping.
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science 13
2015-04-24 20:26:36
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