1. Counting Atoms
    1. What is the mass in grams of 7.5 x 10 15 atoms of nickel, Ni? Show given information, formula, plug into formula, cancellation of units, and follow the rules for significant figures. (7.3 x 10 -7 g Ni)
    2. How many atoms of sulfur, S, are in 4.00 g of sulfur? Show given information, formula, plug into formula, cancellation of units, and follow the rules for significant figures. (7.51 x 10 -22 atoms S)

    3. What mass of gold, Au, Contains the same number of atoms as 9.0 g of aluminum, Al? Show given information, formula, plug into formula, cancellation of units, and follow the rules for significant figures. (66 g Au)
    4. For each of the following, indicate the number of protons, electrons, and neutrons and show all work:
      a) sodium-23
      b) calcium=40
      c) 29 64 Cu
      d) 47 108 Ag
    5. Write the nuclear symbol and hyphen notation for each of the following isotopes:
      a) mass number of 28 and atomic number of 14
      b) 26 protons and 30 neutrons
      c) 56 electrons and 82 neutrons
    6. To two decimal places, what is the relative atomic mass and the molar mass of the element potassium, K?
    7. Determine the mass in grams of the following, showing given information, unit cancellation, and follow the rules of significant figures:
      a) 2.00 mol N (28.0 g N)
      b) 3.01 x 10 23 atoms Cl (17.8 g Cl)
    8. Determine the amount in moles of the following, showing given information, unit cancellation, and follow the rules of significant figures:
      a) 12.15 g Mg (0.5000 mol Mg)
      b) 1.50 x 10 23 atoms F (0.249 mol F)
    9. Determine the number of atoms in the following, showing given information, unit cancellation, and follow the rules of significant figures:
      a) 2.50 mol Zn (1.50 x 10 24 atoms Zn)
      b) 1.50 g C (7.52 x 10 22 atoms C)
    10. a) Define isotope.
      b) How are the isotopes of an element alike?
      c) How are the isotopes of an element different?
    11. Define nuclide.
    12. Define the molar mass of an element.
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