Name: _________________________ Date: ____________ Period: ________
Reviewing Important Concepts
10. In each case, decide which represents more mass:
(a) 0.5 mol of Na or 0.5 mol Si
(b) 9.0 g of Na or 0.50 mol Na
(c) 10 atoms of Fe or 10 atoms of K
12. What is the difference between a group or family and a period in the periodic table?
14. Name and give symbols for the following. In each case locate the element in the periodic table by giving the group and period in which the element is found.
(a) three elements that are metals
(b) four elements that are nonmetals
(c) two elements that are metalloids.
Practice Skills
Composition of Atoms
20. Give the mass number of each of the following atoms:
(a) Magnesium with 15 neutrons
(b) Titanium with 25 neutrons
(c) Zinc with 32 neutrons
A
Z
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22. Give the complete symbol ( X) for each of the following atoms:
(a) Potassium with 20 neutrons
(b) Krypton with 48 neutrons
(c) Cobalt with 33 neutrons
24. How many electrons, protons, and neutrons are there in an atom of
(a) Magnesium-24, (
24
Mg)
(b) Tin-119, (
119
Sn)
(c) Thorium-232, (
232
Th)
Isotopes
28. Cobalt has three radioactive isotopes used in medical studies. Atoms of these isotopes have
30, 31, and 33 neutrons, respectively. Give the symbol for each of these isotopes.
Isotope Abundance & Atomic Number
30. Thallium has two stable isotopes,
203
Tl and
205
Tl. Which is the more abundant of the two?
(hint; your periodic table will be of use)
34. Gallium has two naturally occurring isotopes, 69 Ga and 71 Ga, with masses of 68.9257 amu and 70.9249 amu, respectively. Calculate the percent abundance of these isotopes.
Atoms & the Mole
36. Calculate the mass, in grams, of:
(a) 2.5 mol of aluminum
(b)
1.25 × 10 −3
mol of iron
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38. Calculate the amount (moles) represented by each of the following:
(a) 127.08 g of Cu
(b) 5.0 mg of americium
General Questions
46. Fill in the blanks in the table (one column per element).
Symbol 28 Ni 33 S _______
# Protons
# Neutrons
_______
_______
# Electrons _______
Name of element _______
_______
_______
_______
_______
10
10
_______
_______
52. Which of the following is impossible? Explain why.
(a)
Silver foil that is 1.2 × 10 −4
m thick.
(b) A sample of potassium that contains 1.784 × 10 24 atoms.
(c)
A gold coin of mass 1.23 × 10 −3
kg.
(d)
3.43 × 10 −27
mol S
8
.
54. The plot shows the variation in density with atomic number for the first 36 elements. Use this plot to answer the following questions:
(a) What three elements in this series have the highest density.
What is their approximate density?
Are these elements metals or nonmetals?
(b) Which element in the second period has the largest density?
Which element in the third period has the largest density?
What do these two elements have in common?
(c) Some elements have densities so low that they do not show up on the plot.
What elements are these?
What property do they have in common?
_______
_______
30
25
_______
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56. Reviewing the periodic table:
(a) Name an element in Group 2A.
(b) Name an element in the third period.
(c) What element is in the second period in Group 4A?
(d) What element is in the third period in Group 6A?
(e) What halogen is in the fifth period?
(f) What alkaline earth element is in the third period?
(g) What noble gas element is in the fourth period?
(h) Name the nonmetals in Group 6A and the third period.
(i) Name a metalloid in the fourth period.
58. If you have 0.00789 g of the gaseous element krypton, how many moles does this represent?
How many atoms?
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