Name:

7. If the nucleus of an atom were the size of a medium-sized orange (a diameter of about
    6 cm), what would be the diameter of the atom?

12. What was incorrect about Mendeleev's original concept of the periodic chart? What is the
      modern law chemical periodicity, and how is it related to Mendeleev's ideas?

15. Name and give the symbols for three transition elements in the fourth period. Look up
    each choice in a dictionary and make a list of the properties given by the dictionary. Also,
    list the uses given by the dictionary for these elements.

23. Give the complete symbol ( ^A_X) for the following atoms: sodium, argon, and gallium.
                                            z

25. How many electrons, protons, and neutrons are there in an atom of: calcium-40,
    tin-119, plutonium-244?

33. Verify that the atomic mass of lithium is 6.94 amu, given the following information:
    Li-6 mass = 6.015121 amu, percent abundance = 7.50%; Li-7 mass = 7.016003 amu,
    percent abundance = 92.50%

39. Which period in the periodic chart is yet incomplete? What well known property
    characterizes them?

41. Calculate the number of grams in:
    a. 2.5 mol of boron
    b. 0.015 mol oxygen
    c. 1.25 x 10^-3 mol iron.
    d. 653 mol of helium.

43. Calculate the number of moles represented by each of the following:
    a. 127.08 g of Cu
    b. 20.0 g of Ca
    c. 16.75 g of Al
    d. 0.012 g of K
    e. 5.0 g of Am

49. If you have a35.67 g piece of chromium metal on your car, how many atoms of
    chromium are in the piece?

55. The figure below shows the mass spectrum of the isotopes of antimony. What are the
    symbols of the isotopes? Which is the more abundant isotope? How many protons,
    neutrons and electrons does this isotope have? Calculate the approximate atomic mass
    of antimony.

57. When an athelete tears ligaments and tendons, they can be surgically attached to bone
    to keep them in place until they heal. A problem with current techniques, however, is that
    the screws and washers used are often too big to be positioned properly. A new titanium
    containing device (see drawing) has therefore been invented to correct the problem.

    a. What are the symbol, atomic number, and atomic mass of titanium?
    b. In what group and period is it found? Name the other elements of its group.
    c. What chemical properties do you suppose make titanium an excellent choice
        for this and other surgical applications?
    d. Use a dictionary or the Handbook of Chemistry and Physics (otherwise known as the
        reference book from hell) and make a list of the properties and uses of this metal.