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CHAPTER 10
MODERN ATOMIC THEORY AND THE PERIODIC TABLE
SOLUTIONS TO REVIEW QUESTIONS
1. Wavelength is defined as the distance between consecutive peaks in a wave. It is generally symbolized
by the Greek letter lambda, l.
Frequency is a measure of the number of waves that pass a specific point every second. It is generally
symbolized by the Greek letter nu, n.
2. Visible light ranges in wavelength from about 4 107 m to 7 107 m. Red light has a longer
wavelength than blue light.
3. Photon
4. An electron orbital is a region in space around the nucleus of an atom where an electron is most probably
found.
5. The electrons in the atom are located in the orbitals with the lowest energies.
6. The main difference is that the Bohr orbit has an electron traveling a specific path around the nucleus
while an orbital is a region in space where the electron is most probably found.
7. Bohr’s model was inadequate since it could not account for atoms more complex than hydrogen. It was
modified by Schr€
odinger into the modern concept of the atom in which electrons exhibit wave and
particle properties. The motion of electrons is determined only by probability functions as a region in
space, or a cloud surrounding the nucleus.
8. Both 1s and 2s orbitals are spherical in shape and located symmetrically around the nucleus. The sizes of
the spheres are different—the radius of the 2s orbital is larger than the 1s. The electrons in 2s orbitals are
located further from the nucleus.
9. The letters used to designate the energy sublevels are s, p, d, and f.
10. 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p.
11. s–2 electrons per shell
p–6 electrons per shell after the first energy level
d–10 electrons per shell after the second energy level.
12. s orbital.
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- Chapter 10 p orbitals
z
z
z
Px
Py
x
Pz
x
y
x
y
13. A second electron may enter an orbital already occupied by an electron if its spin is opposite that of the
electron already in the orbital and all other orbitals of the same sublevel contain an electron.
14. The valence shell is the outermost energy level of an atom.
15. Valence electrons are the electrons located in the outermost energy level of an atom. Valence electrons
are involved in bonding. They are important because ion formation involves the gain or loss of valence
electrons. Covalent bonding involves sharing valence electrons.
16. 4 is the fourth principal energy level
f indicates the energy sublevel
3 indicates the number of electrons in the f sublevel
17. Ir, Zr, and Ag are not representative elements; they are transition elements.
18. Elements in the p-block all have one to six electrons in the p sublevel.
19. Atomic #
6
7
8
15
33
Symbol
C
N
O
P
As
Elements with atomic numbers 7, 15, and 33 are all in the same group on the periodic table. They have an
outermost electron structure of s2p3.
20. The first three elements that have six electrons in their outermost energy level are O, S, and Se.
21. The greatest number of elements in any period is 32. The 6th period has this number of elements.
22. The elements in Group A always have their last electrons in the outermost energy level, while the last
electrons in Group B lie in an inner level.
23. Pairs of elements which are out of sequence with respect to atomic masses are: Ar and K; Co and Ni; Te
and I; Th and Pa; U and Np; Pu and Am; Lr and Rf; Sg and Bh.
24. Dimitri Mendeleev, of Russia and Lothar Meyer, of Germany both independently published results that
led to the current periodic table.
25. Dimitri Mendeleev is credited with being the father of the modern periodic table.
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SOLUTIONS TO EXERCISES
1.
(a)
(b)
(c)
(d)
Element
Li
Mg
Ca
F
Total Electrons
3
12
20
9
Valence Electrons
1
2
2
7
(a)
(b)
(c)
(d)
Element
Na
As
P
Al
Total Electrons
11
33
15
13
Valence Electrons
1
5
5
3
2.
3. Electron configurations
4.
(a)
(b)
(c)
(d)
Sc
Rb
Br
S
1s22s22p63s23p64s23d1
1s22s22p63s23p64s23d104p65s1
1s22s22p63s23p64s23d104p5
1s22s22p63s23p4
(a)
(b)
(c)
(d)
Mn
Kr
Ga
B
1s22s22p63s23p64s23d5
1s22s22p63s23p64s23d104p6
1s22s22p63s23p64s23d104p1
1s22s22p1
5. The spectral lines of hydrogen are produced by energy emitted when the electron from a hydrogen atom,
which has absorbed energy, falls from a higher energy level to a lower energy level (closer to the
nucleus).
6. Bohr said that a number of orbits were available for electrons, each corresponding to an energy level.
When an electron falls from a higher energy orbit to a lower energy orbit, energy is given off as a specific
wavelength of light. Only those energies in the visible range are seen in the hydrogen spectrum. Each line
corresponds to a change from one orbit to another.
7. 16 orbitals in the 4th principal energy level; 1 in s, 3 in p, 5 in d, and 7 in f. The s and p orbitals are in the
4th period, the d orbitals are in the 5th period, and the f orbitals are in the 6th period.
8. 18 electrons in third energy level; 2 in s, 6 in p, 10 in d
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- Chapter 10 9.
10.
11.
12.
(a)
14
7N
(b)
35
17 Cl
(c)
65
30 Zn
(d)
91
40 Zr
(e)
127
53 I
(a)
28
14 Si
(b)
32
16 S
(c)
40
18 Ar
(d)
51
23 V
(e)
31
15 P
(a)
O
1s22s22p4
(b)
Ca
1s22s22p63s23p64s2
(c)
Ar
1s22s22p63s23p6
(d)
Br
1s22s22p63s23p64s23d104p5
(e)
Fe
1s22s22p63s23p64s23d6
(a)
Li
1s22s1
(b)
P
1s22s22p63s23p3
(c)
Zn
1s22s22p63s23p64s23d10
(d)
Na
1s22s22p63s1
(e)
K
1s22s22p63s23p64s1
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- Chapter 10 13. (a)
(b)
(c)
(d)
14. (a)
(b)
Incorrect – the 2 p sublevel should be completely filled before the 3s sublevel is populated.
Correct
Correct
Incorrect – electrons in the 3d sublevel should not be paired until all 3d orbitals are populated.
Correct
Incorrect – the 3d sublevel should be populated before the 4p sublevel.
(c)
Incorrect – the second electron in the 4s orbital must be represented by a down arrow
(d)
Correct
15. (a) Neon
(b) Phosphorus
(c) Gallium
(d) Manganese
16. (a)
(b)
(c)
(d)
Nitrogen
Nickel
Calcium
Sulfur
17. (a) fluorine, F
(b) sodium, Na
(c) sulfur, S
(d) nickel, Ni
18. (a) boron, B
(b) silicon, Si
(c) lead, Pb
(d) tellurium, Te
19.
(a)
Titanium (Ti)
(b)
Argon (Ar)
(c)
Arsenic (As)
(d)
Bromine (Br)
(e)
Manganese (Mn)
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- Chapter 10 20.
21.
22.
(a)
Phosphorus (P)
(b)
Zinc (Zn)
(c)
Calcium (Ca)
(d)
Selenium (Se)
(e)
Potassium (K)
(a)
F
(b)
S
(c)
Co
(d)
Kr
(e)
Ru
(a)
Cl
(b)
Mg
(c)
Ni
(d)
Cu
(e)
Ba
23. (a)
24.
32
16 S
(b)
60
28 Ni
(a)
13p
14n
2e8e3e
27
13 Al
(b)
22p
26n
2e8e8e4e
48
22 Ti
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- Chapter 10 25. The eleventh electron of sodium is located in the third energy level because the first and second levels are
filled. Also the properties of sodium are similar to the other elements in Group 1A.
26. The last electron in potassium is located in the fourth energy level because the 4s orbital is at a lower
energy level than the 3d orbital. Also the properties of potassium are similar to the other elements in
Group 1A.
27. Noble gases all have filled s and p orbitals in the outermost energy level.
28. Noble gases each have filled s and p orbitals in the outermost energy level.
29. Moving from left to right in any period of elements, the atomic number increases by one from one
element to the next and the atomic radius generally decreases. Each period (except period 1) begins with
an alkali metal and ends with a noble gas. There is a trend in properties of the elements changing from
metallic to nonmetaliic from the beginning to the end of the period.
30. The elements in a group have the same number of outer energy level electrons. They are located
vertically on the periodic table.
31.
(a)
4
(b)
6
(c)
1
(d)
7
(e)
3
32.
(a)
5
(b)
5
(c)
6
(d)
2
(e)
3
33. The outermost energy level contains one electron in an s orbital.
34. All of these elements have a s2d10 electron configuration in their outermost energy levels.
35. (a) and (g)
(b) and (d)
36. (a) and (f)
(e) and (h)
37. 12, 38 since they are in the same group or family of elements.
38. 7, 33 since they are in the same group or family of elements.
39.
(a)
(b)
K, metal
Pu, metal
(c)
(d)
40.
(a)
(b)
I, nonmetal
W, metal
(c)
(d)
S, nonmetal
Sb, metalloid
Mo, metal
Ge, metalloid
41. Period 6, lanthanide series, contains the first element with an electron in an f orbital.
42. Period 4 Group 3B contains the first element with an electron in a d orbital.
43. Group 7A contain 7 valence electrons.
Group 7B contain 2 electrons in the outermost level and 5 electrons in an inner d orbital.
Group A elements are representative while Group B elements are transition elements.
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- Chapter 10 44. Group 3A contain 3 valence electrons.
Group 3B contain 2 electrons in the outermost level and one electron in an inner d orbital.
Group A elements are representative while Group B elements are transition elements.
45. (a) arsenic
(b) cobalt
(c) lithium
(d) chlorine
46. (a) lead
(b) samarium
(c) gallium
(d) iridium
47. The valence energy level of an atom can be determined by looking at what period the element is in. Period
1 corresponds to valence energy level 1, period 2 to valence energy level 2 and so on. The number of
valence electrons for element’s 1–18 can be determined by looking at the group number. For example,
boron is under Group 3A, therefore it has three valence shell electrons.
48.
(a) Mg
(b) P
(c) K
(d) F
(e) Se
(f) N
3s 3p
1s 2s 2p 4s
1s 2s 2p 3s 3p 2s 2p
1s 4s 3d 4p
1s 2s 2p 3s 3p 2s 2p
1s 1s22s22p6 3s2
2
2
6
2
2
6
2
2
2
2
2
2
2
3
2
6
1
2
6
2
5
6
10
4
3
49. (a) Naþ, (d) F, and (e) Ne have 8 valence electrons.
50.
(a)
(b)
(c)
51. (a)
(b)
(c)
(d)
7A, Halogens
2A, Alkaline Earth Metals
1A, Alkali Metals
(d)
(e)
(f)
8A, Noble Gases
8A, Noble Gases
1A, Alkali Metals
No, the electronic configuration predicted by the periodic table is 1s2 2s2 2p6 3s2 3p6 4s2 3d4.
7:19 g
1 mol
6:022 1023 atoms
3
ð5:00 cm Þ
¼ 4:16 1023 atoms Cr
1 cm3
52:00 g
1 mol
3
4
4
V ¼ pr3 ¼ p 1:40 108 ¼ 1:15 1023 cm3
3
3
1 atom
3
ð5:00 cm Þ
¼ 4:35 1023 atoms Cr
1:15 1023 cm3
52. Each of the different elements has a characteristic emission spectra which will be observed as different
colors in the fireworks.
53. Sb 1s22s22p63s23p64s23d104p65s24d105p3 or [Kr] 5s24d105p3
54. Bi 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p3 or [Xe] 6s24f145d106p3
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- Chapter 10 55.
(a)
(b)
The four most abundant elements in the
earth’s crust, seawater, and air are:
Si: 1s22s22p63s23p2
O: 1s22s22p4
2 2
6 2
6 2
Fe: 1s 2s 2p 3s 3p 4s 3d6
Al: 1s22s22p63s23p1
The five most abundant elements in the human body are:
C: 1s22s22p2
H: 1s1
O: 1s22s22p4
Ca: 1s22s22p63s23p64s2
N: 1s22s22p3
56. Maximum number of electrons
(a) Any orbital can hold a maximum of two electrons.
(b) A d sublevel can hold a maximum of ten electrons.
(c) The third principal energy level can hold two electrons in 3s, six electrons in 3p, and ten electrons
in 3d for a total of eighteen electrons.
(d) Any orbital can hold a maximum of two electrons.
(e) An f sublevel can hold a maximum of fourteen electrons.
57. Name of elements
(a) Magnesium
(b)
Phosphorus
(c) Argon
58. Nitrogen has more valence electrons on more energy levels than hydrogen. More varied electron
transitions are possible.
59.
(a) Ne
(b) Ge
(c) F
(d) N
60. The outermost electron structure for the elements in 7A is s2p5.
61. Transition elements are found in Groups 1B–8B, lanthanides and actinides.
62. In transition elements the last electron added is in a d or f orbital. The last electron added in a
representative element is in an s or p orbital.
63. Elements 7, 15, 33, 51, and 83 all have 5 electrons in their valence shell.
64. Family names
(a)
Alkali Metals
(b)
Alkaline Earth Metals
65. Sublevels
(a)
66.
(a)
(b)
(c)
(d)
(e)
(f)
sublevel p
Na
N
Mo
Ra
As
Ne
(b)
sublevel d
representative element
representative element
transition element
representative element
representative element
noble gas
(c)
sublevel f
metal
nonmetal
metal
metal
metalloid
nonmetal
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Halogens
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- Chapter 10 67. If element 36 is a noble gas, 35 would be in periodic Group 7A and 37 would be in periodic Group 1A.
68. Answers will vary but should at least include a statement about: (1) Numbering of the elements and their
relationship to atomic structure; (2) division of the elements into periods and groups; (3) division of the
elements into metals, nonmetals, and metalloids; (4) identification and location of the representative and
transition elements.
69.
(a)
(b)
The two elements are isotopes.
The two elements are adjacent to each other in the same period.
70. Most gases are located in the upper right part of the periodic table (H is an exception). They are
nonmetals. Liquids show no pattern. Neither do solids, except the vast majority of solids are metals.
71. excited sulfur atom:
electron configuration: 1s22s22p63s13p5
orbital diagram:
72. Electrons are located in seven principal energy levels. The outermost energy level has one electron
residing in a 7s orbital.
73. Metals are located on the left side of the periodic table. The elements in Group 1A have only one valence
electron and those in Group 2A have only two valence electrons.
All metals easily lose their valence electrons to obtain a Noble Gas configuration. Nonmetals are
located on the right side of the periodic table where they are only a few electrons short of a noble gas
configuration. Nonmetals gain valence electrons to obtain a noble gas configuration.
74. On the periodic table, the period number corresponds to the principal energy level in which the s and p
sublevels are filling. The group number of the Main Representative elements corresponds to the number
of electrons filling in the principal energy level. Groups 1A and 2A are known as the s-block elements and
Groups 3A through 8A are known as the p-block elements.
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