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CHAPTER 10
MODERN ATOMIC THEORY AND THE PERIODIC TABLE
SOLUTIONS TO REVIEW QUESTIONS
1.
An electron orbital is a region in space around the nucleus of an atom where an electron
is most probably found.
2.
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.
3.
The valence shell is the outermost energy level of an atom.
4.
Valence electrons are the electrons located in the outermost energy level of an atom.
Valence electrons are involved in bonding. They are important because information
involves the gain or loss of valence electrons. Covalent bonding involves sharing valence
electrons.
5.
All the electrons in the atom are located in the orbitals closest to the nucleus.
6.
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.
7.
The letters used to designate the energy sublevels are s, p, d, and f.
8.
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p.
9.
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.
10.
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.
11.
Bohr’s model was inadequate since it could not account for atoms more complex than
hydrogen. It was modified by Schrödinger 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.
12.
s orbital.
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p orbitals
z
z
px
z
py
x
pz
x
x
y
13.
3 is the third energy level
d indicates an energy sublevel
7 indicates the number of electrons in the d sublevel.
14.
Transition elements are found in the center of the periodic table. The last electrons for
these elements are found in the d or f orbitals.
Representative elements are located on either side of the periodic table (Group 1A–7A).
The valence electrons for these elements are found in s and/or p orbitals.
15.
Elements in the s-block all have one or two electrons in their outermost energy level.
These valence electrons are located in an s-orbital.
16.
Atomic #
Symbol
8
O
16
S
34
Se
52
Te
84
Po
All of these elements have an outermost electron structure of s2p4.
17.
F, Cl, Br, I, At (Halogens).
18.
The greatest number of elements in any period is 32. The 6th period has this number of
elements.
19.
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.
20.
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; Sq and Bh.
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CHAPTER 10
SOLUTIONS TO EXERCISES
1.
(a)
(b)
H
B
1 proton
5 protons
(c)
(d)
Sc
U
21 protons
92 protons
2.
(a)
(b)
F
Ag
9 protons
47 protons
(c)
(d)
Br
Sb
35 protons
51 protons
3.
(a)
B
1s22s22p 1
(b)
Ti
1s22s22p 63s23p 64s23d2
(c)
Zn
1s22s22p 63s23p 64s23d10
(d)
Sr
1s22s22p 63s23p 64s23d104p 65s2
(a)
Cl
1s22s22p 63s23p 5
(b)
Ag
1s22s22p 63s23p 64s23d104p 65s14d10
(c)
Li
1s22s1
(d)
Fe
1s22s22p 63s23p 64s23d6
(e)
I
1s22s22p63s23p64s23d104p65s24d105p5
4.
5.
The spectral lines of hydrogen are produced by energy emitted when the electron from on
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.
9 orbitals in the third energy level: 3s, 3p x , 3p y , 3p z plus five d orbitals.
8.
32 electrons in the fourth energy level.
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9.
10.
11.
(a)
7p
7n
2e5e
14
7N
(b)
17p
18n
2e8e7e
35
17Cl
(c)
30p
35n
2e8e18e2e
65
30Zn
(d)
40p
51n
2e8e18e10e2e
91
40Zr
(e)
53p
74n
2e8e18e18e7e
(a)
14p
14n
2e8e4e
28
14Si
(b)
16p
16n
2e8e6e
32
16S
(c)
18p
22n
2e8e8e
40
18Ar
(d)
23p
28n
2e8e11e2e
51
23V
(e)
15p
16n
2e8e5e
31
15P
127
53I
(a)
O
1s22s22p 4
(b)
Ca
1s22s22p 63s23p 64s2
(c)
Ar
1s22s22p 63s23p 6
(d)
Br
1s22s22p 63s23p 64s23d104p 5
(e)
Fe
1s22s22p 63s23p 64s23d6
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12.
13.
14.
15.
16.
17.
(a)
Li
1s22s1
(b)
P
1s22s22p 63s23p 3
(c)
Zn
1s22s22p 63s23p 64s23d10
(d)
Na
1s22s22p 63s1
(e)
K
1s22s22p 63s23p 64s1
(a)
Mg
(c)
Ni
(b)
Al
(d)
Mn
(a)
Sc
(c)
Sn
(b)
Zn
(d)
Cs
atomic No.
electron structure
(a)
8
1s22s22p 4
(b)
11
1s22s22p 63s1
(c)
17
1s22s22p 63s23p 5
(d)
23
1s22s22p 63s23p 64s23d3
(e)
28
1s22s22p 63s23p 64s23d8
(f)
34
1s22s22p 63s23p 64s23d104p 4
atomic No.
electron structure
(a)
9
[He]2s22p 5
(b)
26
[Ar]4s23d6
(c)
31
[Ar]4s23d104p 1
(d)
39
[Kr]5s24d1
(e)
52
[Kr]5s24d105p 4
(f)
10
[He]2s22p 6
(a)
Titanium (Ti)
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(b)
Argon (Ar)
qp qp qp qp qp qp qp qp qp (c)
Arsenic (As)
qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp q q q (d)
Bromine (Br)
qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp q (e)
Manganese (Mn) qp qp qp qp qp qp qp qp qp qp q q q q q 18.
(a)
Phosphorus (P)
qp qp qp qp qp qp q q q (b)
Zinc (Zn)
qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp `
(c)
Calcium (Ca)
qp qp qp qp qp qp qp qp qp qp (d)
Selenium (Se)
qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp q q 19.
(e)
Potassium (K)
qp qp qp qp qp qp qp qp qp q (a)
F
qp qp qp qp q (b)
S
qp qp qp qp qp qp qp q q (c)
Co
qp qp qp qp qp qp qp qp qp qp qp qp q q q (d)
Kr
qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp (e)
Ru
qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp q qp qp q q q - 123 -
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20.
(a)
Cl
qp qp qp qp qp qp qp qp q (b)
Mg
qp qp qp qp qp qp (c)
Ni
qp qp qp qp qp qp qp qp qp qp qp qp qp q q (d)
Cu
qp qp qp qp qp qp qp qp qp q qp qp qp qp qp (e)
Ba
qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp qp 21.
(a)
32
16S
22.
(a)
13p
14n
2e8e3e
27
13Al
(b)
22p
26n
2e8e10e2e
48
22Ti
(b)
60
28Ni
23.
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.
24.
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.
25.
Noble gases all have filled s and p orbitals in the outermost energy level.
26.
Noble gases each have filled s and p orbitals in the outermost energy level.
27.
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 nonmetallic from the beginning to
the end of the period.
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28.
The elements in a group have the same number of outer energy level electrons. They are
located vertically on the periodic table.
29.
(a)
4
(b)
6
(c)
1
(d)
7
(e)
3
30.
(a)
5
(b)
5
(c)
6
(d)
2
(e)
3
31.
The outermost energy level contains one electron in an s orbital.
32.
All of these elements have a s2d10 electron configuration in their outermost energy levels.
33.
(a) and (g)
(b) and (d)
34.
(a) and (f)
(e) and (h)
35.
12, 38 since they are in the same periodic group.
36.
7, 33 since they are in the same periodic group.
37.
(a)
(b)
K, metal
Pu, metal
(c)
(d)
S, nonmetal
Sb, metalloid
38.
(a)
(b)
I, nonmetal
W, metal
(c)
(d)
Mo, metal
Ge, metalloid
39.
Period 6, lanthanide series, contains the first element with an electron in an f orbital.
40.
Period 4 Group 3B contains the first element with an electron in a d orbital.
41.
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.
42.
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.
43.
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.
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44.
(a)
(b)
(c)
(d)
(e)
valence energy level 2, 1 valence electron
valence energy level 3, 7 valence electrons
valence energy level 3, 4 valence electrons
valence energy level 3, 6 valence electrons
valence energy level 2, 2 valence electrons
45.
(a)
Na + , (d) F - and (e) Ne have 8 valence electons.
46.
(a)
(b)
(c)
7A, Halogens
2A, Alkaline Earth Metals
1A, Alkali Metals
47.
(a)
The four most abundant elements in the earth’s crust, seawater, and air are:
O: 1s22s22p4 Si: 1s22s22p63s23p2 Al: 1s22s22p63s23p1
Fe: 1s22s22p63s23p64s23d6
(b)
The five most abundant elements in the human body are:
O: 1s22s22p4 C: 1s22s22p2 H: 1s1 N: 1s22s22p3 Ca: 1s22s22p63s23p64s2
(d)
(e)
(f)
8A, Noble Gases
8A, Noble Gases
1A, Alkali Metals
48.
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.
49.
Name of elements
(a) Magnesium
50.
(b) Phosphorus
(c)
Argon
Nitrogen has more valence electrons on more energy levels. More varied electron
transitions are possible.
51.
1.5
1.5 * 108
=
150,000,000
=
1
1.0 * 10-8
52.
(a)
53.
The outermost electron structure for both sulfur and oxygen is s2p 4.
54.
Transition elements are found in Groups 1B–8B lanthanides and actinides.
55.
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.
Ne
(b)
Ge
(c)
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56.
Elements number 8, 16, 34, 52, 84 all have 6 electrons in their outer shell.
57.
Family names
(a) Alkali Metals (b)
Alkaline Earth Metals
Sublevels
(a) sublevel p
sublevel d
58.
Na
N
Mo
Ra
As
Ne
(b)
representative element
representative element
transition element
representative element
representative element
noble gas
(c)
(c)
Halogens
sublevel f
59.
(a)
(b)
(c)
(d)
(e)
(f)
metal
nonmetal
metal
metal
metalloid
nonmetal
60.
If element 36 is a noble gas, 35 would be in periodic Group 7A and 37 would be in
periodic Group 1A.
61.
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.
62.
(a)
(b)
(c)
(d)
[Rn]7s25f 146d107p 5
7 valence electrons, 7s27p 5
F, Cl, Br, I, At
halogen family, Period 7
63.
(a)
(b)
The two elements are isotopes.
The two elements are adjacent to each other in the same period.
64.
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.
65.
excited sulfur atom:
electron configuration: 1s22s22p 63s13p 5
orbital diagram:
qp qp qp qp qp q qp qp q 66.
Electrons are located in seven principal energy levels. The outermost energy level has one
electron residing in a 7s orbital.
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67.
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 tow 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 1 or 2
electrons short of a noble gas configuration. Nonmetals gain valence electrons to obtain a
noble gas configuration.
68.
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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