Question
According to the law of definite proportions
a) if the same two elements form two
different compounds, they do so in the
same ratio.
b) it is not possible for the same two
elements to form more than one
compound.
c) the ratio of the masses of the elements in
a compound is always the same.
d) the total mass after a chemical change is
the same as before the change.
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7|1
Answer
c) the ratio of the masses of the elements
in a compound is always the same.
This describes the result of elements
combining to form compounds.
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7|2
Question
Ernest Rutherford
a) determined the charge of a single
electron.
b) proposed that cathode rays contained
electrons.
c) determined the existence of neutrons.
d) conducted the “gold foil” experiment.
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7|3
Answer
d) conducted the “gold foil” experiment.
Robert Millikan determined the charge of
a single electron. J.J. Thomson proposed
the “plum pudding” model of the atom.
James Chadwick determined the
existence of neutrons.
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7|4
Question
How many of the following did Dalton not discuss
in his atomic theory?
I.
II.
III.
IV.
V.
a) One
Isotopes
Ions
Protons
Neutrons
Electrons
b) Two
c) Three
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d) Four
e) Five
7|5
Answer
e)
Five
Dalton only addressed matter’s basic unit
as atoms in his theory.
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7|6
Question
The element Rhenium (Re) exists as two
stable isotopes and 18 unstable isotopes.
Rhenium-185 isotope has in its nucleus
a)
b)
c)
d)
75 protons and 75 neutrons.
75 protons and 130 neutrons.
130 protons and 75 neutrons.
75 protons and 110 neutrons.
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7|7
Answer
d)
75 protons and 110 neutrons.
The mass number is the sum of the
protons (same as the atomic number) and
neutrons.
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7|8
Question
Which of the following statements are true?
I. The number of protons is the same for all
neutral atoms of an element.
II. The number of electrons is the same for all
neutral atoms of an element.
III. The number of neutrons is the same for all
neutral atoms of an element.
a)
b)
c)
d)
e)
I, II, and III are all true.
Only I and II are true.
Only II and III are true.
Only I and III are true.
I, II, and III are all false.
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7|9
Answer
b)
Only I and II are true.
For neutral atoms of an element, the number of
protons equals the number of electrons and is
the same as the atomic number. However, the
number of neutrons differs depending on the
isotopes.
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7 | 10
Question
10
5B
Boron (B) has two isotopes:
with mass of
10.013 amu and 115B with mass of 11.009 amu.
The average atomic mass of boron is 10.81
amu. The fractional abundance of each isotope
is
a)
b)
c)
d)
e)
0.990 of Boron-10 and 0.010 of Boron-11.
0.804 of Boron-10 and 0.196 of Boron-11.
0.500 of Boron-10 and 0.500 of Boron-11.
0.196 of Boron-10 and 0.804 of Boron-11.
0.010 of Boron-10 and 0.990 of Boron-11.
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7 | 11
Answer
d) 0.196 of Boron-10 and 0.804 of Boron-11.
Since the average atomic mass is closer to that of
Boron-11, the fractional abundance of Boron-11
must be higher than that of Boron-10. The
average atom mass is significantly less than that
of Boron-11, so there is a significant fractional
abundance of Boron-10.
(10.013 amu × 0.196) + (11.009 amu × 0.804) = 10.81 amu
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7 | 12
Question
An ion is formed
a) by either adding or subtracting protons
from the atom.
b) by either adding or subtracting electrons
from the atom.
c) by either adding or subtracting neutrons
from the atom.
d) All of the above can form an ion.
e) Two of the above can form an ion.
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7 | 13
Answer
b) by either adding or subtracting
electrons from the atom.
The atoms of an element form ions when
electrons are gained or lost.
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7 | 14
Question
What is the wavelength (in nm) of
electromagnetic radiation that has a
frequency of 7.45 × 1014/s?
(Hint: c = 3.00 × 108 m/s and h = 6.63 × 10−34
J.s)
a) 4.03 × 10−7 nm
b) 403 nm
c) 4.03 nm
d) 2.24 × 1014 nm
e) 1.34 × 10−6 nm
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7 | 15
Answer
b) 403 nm
For all electromagnetic radiation c = . So,
c
 

9
3.00  108 m/ s
10
nm
7

= 4.02  10 m 
= 402 nm.
14
7.45  10 / s
1m
Be sure to convert to the desired units.
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7 | 16
Question
Which form of electromagnetic radiation
has the shortest wavelengths?
a)
b)
c)
d)
e)
Gamma rays
Microwaves
Radio waves
Infrared radiation
X-rays
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7 | 17
Answer
a) Gamma rays
The radiation with the shortest
wavelength is of highest energy.
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7 | 18
Question
Which form of electromagnetic radiation
has the lowest energy?
a)
b)
c)
d)
Red light
Yellow light
Blue light
All visible light has the same energy.
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7 | 19
Answer
a) Red light
Red light is closest to the infrared region
and so it has the lowest energy.
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7 | 20
Question
Which form of electromagnetic radiation
has the shortest wavelength?
a)
b)
c)
d)
Red light
Yellow light
Blue light
All visible light has the same
wavelength.
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7 | 21
Answer
c) Blue light
The radiation with the shortest
wavelength is of highest energy. Blue
light is closest to ultraviolet light.
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7 | 22
Question
Which form of electromagnetic radiation
has the lowest frequency?
a)
b)
c)
d)
Red light
Yellow light
Blue light
All visible light has the same frequency.
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7 | 23
Answer
a) Red light
The radiation with the lowest frequency
has the lowest energy.
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7 | 24
Question
Which form of electromagnetic radiation
has the slowest speed?
a)
b)
c)
d)
Red light
Yellow light
Blue light
All visible light has the same speed.
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7 | 25
Answer
d) All visible light has the same speed.
All electromagnetic radiation, which
includes visible light, has the same speed
~3.00 × 108 m/s.
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7 | 26
Question
The photoelectric effect predicts that
a) electrons can be ejected from the surface of a
metal using a vacuum.
b) electrons can be ejected from the surface of a
metal using light with a frequency greater than
a certain threshold value.
c) electrons can be ejected from the surface of a
metal using light with a frequency less than
a certain value.
d) electrons can be ejected from the surface of a
metal using light with a frequency greater than
a certain threshold value that is the same for all
metals.
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7 | 27
Answer
b) electrons can be ejected from the surface of
a metal using light with a frequency greater
than a certain threshold value.
The photoelectric effect predicts that electrons
can be ejected from the surface of a metal using
light with a frequency greater than a certain
threshold value. The threshold value is
characteristic of the metal.
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7 | 28
Question
From the following list of observations, choose
the one that most clearly supports the following
conclusion:
Electrons have wave properties.
a)
b)
c)
d)
e)
Emission spectrum of hydrogen
The photoelectric effect
Scattering of alpha particles by metal foil
Diffraction
Cathode “rays”
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7 | 29
Answer
d) Diffraction
Diffraction patterns are produced by
waves.
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7 | 30
Question
From the following list of observations, choose
the one that most clearly supports the following
conclusion:
Electrons in atoms have quantized energies.
a)
b)
c)
d)
e)
Emission spectrum of hydrogen
The photoelectric effect
Scattering of alpha particles by metal foil
Diffraction
Cathode “rays”
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7 | 31
Answer
a) Emission spectrum of hydrogen
The emission spectrum shows only
certain colors of light, providing support
for quantized energy levels.
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7 | 32
Question
Which of the following statements is false?
a) The energy of electromagnetic radiation
increases as its frequency increases.
b) An excited atom can return to its ground state by
absorbing electromagnetic radiation.
c) An electron in the n = 4 state in the hydrogen
atom can go to the n = 2 state by emitting
electromagnetic radiation at the appropriate
frequency.
d) The frequency and wavelength of
electromagnetic radiation are inversely
proportional to each other.
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7 | 33
Answer
b) An excited atom can return to its ground
state by absorbing electromagnetic radiation.
An excited atom returns to its ground state by
releasing energy in the form of electromagnetic
radiation.
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7 | 34
Question
For which of the following electron transitions
for a hydrogen atom does the light emitted have
the longest wavelength?
a)
b)
c)
d)
e)
n = 4 to n = 3
n = 4 to n = 2
n = 4 to n = 1
n = 3 to n = 2
n = 2 to n = 1
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7 | 35
Answer
a) n = 4 to n = 3
Energy is inversely related to wavelength, so
the smaller the energy change, the longer the
wavelength. The transition n = 4 to n = 3 has
the smallest energy change of all of the options.
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7 | 36
Question
The quantum number n
a) can have the value of any integer.
b) distinguishes orbitals with different
shapes.
c) is known as the principal quantum
number.
d) refers to the orientation of the spin axis
of the electron.
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7 | 37
Answer
c) is known as the principal quantum
number.
The principal quantum number is n and can
have only positive integer values of 1, 2, 3, and
so on. The quantum number l distinguishes
orbitals with different shapes. The quantum
number ms refers to the orientation of the spin
axis of the electron.
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7 | 38
Question
If the l quantum number is 3, what are the
possible values of ml ?
a) 3, 2, 1
b) 3, 2, 1, 0
c) 3, 2, 1, 0, −1, −2, −3
d) 2, 1
e) 2, 1, 0
f) 2, 1, 0, −1, −2
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7 | 39
Answer
c) 3, 2, 1, 0, −1, −2, −3
The allowed values for ml are the integers
between −l and l.
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7 | 40
Question
What is the subshell notation when n = 3,
and l = 2?
a)
b)
c)
d)
3s
3p
3d
3f
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7 | 41
Answer
c) 3d
The subshell notation includes the principal
quantum number n followed by the letter
designation for the orbital type (l = 0 is denoted
by s; l = 1 is denoted by p; l = 2 is denoted by d;
and l = 3 is denoted by f).
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7 | 42
Question
A ground state electron in the hydrogen atom is
given just enough energy to get to n = 2. Which
orbital will the electron occupy?
a)
b)
c)
d)
e)
The 2s orbital
The 2px orbital
The 2py orbital
The 2pz orbital
Each of the above is equally likely.
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7 | 43
Answer
e) Each of the above is equally likely.
Because the hydrogen atom has only one
electron, the 2s and 2p orbitals are
degenerate (have the same energy).
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7 | 44
Question
Which of the following combinations of
quantum numbers is not allowed?
a)
b)
c)
d)
e)
n
l
ml
ms
1
3
2
4
4
1
0
1
3
2
0
0
−1
−2
0
½
−½
½
−½
½
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7 | 45
Answer
a)
1
1
0
½
Electrons with n = 1 can only have values
for l of 0.
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7 | 46
Question
How many electrons can be described by
the quantum numbers n = 3, l = 3, ml = 1?
a) 0
b) 1
c) 2
d) 6
e) 10
f) 14
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7 | 47
Answer
a) 0
Electrons with n = 3 can only have values
for l of 0, 1, or 2.
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7 | 48
Question
How many electrons can be described by
the quantum numbers n = 3, l = 2, ml = −1?
a)
b)
c)
d)
e)
f)
0
1
2
6
10
14
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7 | 49
Answer
c) 2
Electrons with n = 3 can have values for l of 0, 1,
or 2. Electrons with l = 2 can have values for ml
of −2, −1, 0, 1, or 2. Thus, n = 3, l = 2, ml = −1 is
allowed. Since ml can be +1/2 or −1/2, two
electrons can share these values of n, l, and ml .
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7 | 50
Question
According to the Aufbau principle (or the
building-up principle), in writing a groundstate electron configuration of an atom,
the orbital that is filled immediately after
the 3d orbital is filled is
a) the 3p orbital.
b) the 4p orbital.
c) the 4s orbital.
d) the 4d orbital.
e) the 3f orbital.
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7 | 51
Answer
b) the 4p orbital.
The correct order of filling orbitals according to
the Aufbau principle is 1s, 2s, 2p, 3s, 3p, 4s, 3d,
4p, 5s, 4d, 5p, ...
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7 | 52
Question
How many of the following electron
configurations for the species in their ground
state are correct?
Ca:
Mg:
V:
As:
P:
a)
b)
c)
d)
e)
1s22s22p63s23p64s2
1s22s22p63s1
[Ar] 3s23d3
[Ar] 4s23d104p3
1s22s22p63p5
One
Two
Three
Four
Five
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7 | 53
Answer
b) Two
The correct electron configurations are
Ca: 1s22s22p63s23p64s2
Mg:1s22s22p63s2
V: [Ar] 4s23d3
As: [Ar] 4s23d104p3
P: 1s22s22p63s23p5
So, only Ca and As were correct.
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7 | 54
Question
Of the following elements, which has
occupied d orbitals in its ground-state
neutral atoms?
a)
b)
c)
d)
e)
Ba
Ca
Si
P
Cl
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7 | 55
Answer
a) Ba
In order for an element to have occupied d
orbitals in its ground-state neutral atoms it must
have an atomic number greater than 20.
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7 | 56
Question
In which groups do all the elements have
the same number of valence electrons?
a)
b)
c)
d)
e)
P, S, Cl
Ag, Cd, Ar
Na, Ca, Ba
P, As, Se
None of these
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7 | 57
Answer
e) None of these
Elements will have the same number of
valence electrons if they are in the same
group in the periodic table.
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7 | 58
Question
An element X has a ground state valence
electron configuration of ns2np5. Which formula
for the compound composed of element X and
nitrogen is most likely?
a)
b)
c)
d)
e)
NX
NX7
NX2
NX3
NX5
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7 | 59
Answer
d) NX3
An element with the valence electron
configuration ns2np5 is a halogen.
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7 | 60
Question
The correct ground-state electron
configuration of copper is
a)
b)
c)
d)
e)
[Ar] 3d94s2.
[Ar] 3d104s1.
[Ar] 3d74s2.
[Ar] 3d84s2.
None are correct.
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7 | 61
Answer
b) [Ar] 3d104s1.
Copper (Z = 29) is one of the exceptions to the
building-up principle. It is more stable to have a
filled 3d orbital and a half-filled 4s orbital than to
have a filled 4s orbital and a partially filled 3d
orbital.
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7 | 62
Question
Which of the following elements have
ground-state electron configurations that
are paramagnetic?
a)
b)
c)
d)
e)
Ca
Zn
Ne
C
None of these
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7 | 63
Answer
d) C
Paramagnetic substances have unpaired
electrons. Since all of the orbitals are filled in
Ca, Zn, and Ne, all of the electrons are paired.
The electron configuration for C is 1s22s22p2.
Since there are three 2p orbitals, Hund’s rule
predicts that the two 2p electrons will be
unpaired.
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7 | 64
Question
Consider the following orderings.
I.
Al < Si < P < Cl
II.
Be < Mg < Ca < Sr
III. I < Br < Cl < F
IV. F < Mg < Na < K
Which of these give(s) a correct trend in size?
a)
b)
c)
d)
e)
I
II
III
IV
At least two of the above give a correct trend in size.
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7 | 65
Answer
e) At least two of the above give a
correct trend in size.
Concerning size, atoms increase going down in
groups and decrease going across in periods.
II. Be < Mg < Ca < Sr and IV. F < Mg < Na < K
are correct.
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7 | 66
Question
Consider the following orderings.
I.
II.
III.
IV.
Al < Si < P < Cl
Be < Mg < Ca < Sr
I < Br < Cl < F
Na+ < Mg2+ < Al3+ < Si4+
Which of these give(s) a correct trend in
ionization energy?
a)
b)
c)
d)
III
I and II
I and IV
I, III, and IV
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7 | 67
Answer
d)
I, III, and IV
Ionization energy increases with increased
positive charge and decreases going down in a
group. Going across in a period, ionization
energy tends to increase with some variations.
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7 | 68
Question
The first ionization energy of magnesium is
about 700 kJ/mol. A good estimate for the
second ionization energy of magnesium is about
a) 700 kJ/mol.
b) 1400 kJ/mol.
c) 70,000 kJ/mol.
d) −700 kJ/mol.
e) −1400 kJ/mol.
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7 | 69
Answer
b) 1400 kJ/mol.
The second ionization energy (IE) should be larger than
the first ionization energy since the electron is being
taken from a positive ion. In this case, the second
electron is taken from the same energy level as the first,
so while the second IE should be greater, it will not be
as great as shown in choice c).
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7 | 70
Question
A hypothetical element, X, has the following ionization
values: First ionization energy: 800 kJ/mol
Second ionization energy: 2450 kJ/mol
Third ionization energy: 3700 kJ/mol
Fourth ionization energy: 25,000 kJ/mol
Fifth ionization energy: 32,800 kJ/mol.
To what family of the periodic table is this element most
likely to belong to?
a)
b)
c)
d)
e)
Group IA
Group IIA
Group IIIA
Group IVA
Group VA
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7 | 71
Answer
c) Group IIIA
The ionization energy of all elements increases from
the first ionization energy to the second ionization
energy, to the third ionization energy, and so on, since
the electron is being taken from an increasingly positive
ion. There is a very large increase in ionization energy
when removing an electron from a noble-gas
configuration—here, the fourth ionization energy
removes an electron from the X3+ ion.
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7 | 72
Question
Which of the following concerning second ionization
energy values is true?
a) That of Al is higher than that of Mg because Mg wants to
lose the second electron, so it is easier to take the
second electron away.
b) That of Al is higher than that of Mg because the electrons
are taken from the same energy level, but the Al atom
has one more proton and Al+ has a filled 3s orbital.
c) That of Al is lower than that of Mg because Mg wants to
lose the second electron, thus the energy change is
greater.
d) That of Al is lower than that of Mg because the second
electron taken from Al is in a p orbital, thus it is easier to
take.
e) The second ionization energies are equal for Al and Mg.
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7 | 73
Answer
b) That of Al is higher than that of Mg because
the electrons are taken from the same
energy level, but the Al atom has one more
proton and Al+ has a filled 3s orbital.
In both cases, the electron is taken from a 3s
orbital. Filled orbitals are more stable than
partially filled orbitals.
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7 | 74
Question
For the atoms Li, N, F, and Na, which of
the following is the correct order from
smallest to largest atomic radius?
a)
b)
c)
d)
e)
Na, F, N, Li
Na, Li, N, F
Li, N, F, Na
N, F, Na, Li
F, N, Li, Na
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7 | 75
Answer
e) F, N, Li, Na
Atomic radius decreases across a row of
the periodic table and increases down a
column of the periodic table.
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Question
Which of the following correctly ranks the
first ionization energies of O, F, Na, S,
and Cs from smallest to largest?
a)
b)
c)
d)
e)
Cs, Na, S, O, F
Cs, S, Na, O, F
F, O, Na, S, Cs
F, O, S, Na, Cs
Na, S, Cs, F, O
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Answer
a) Cs, Na, S, O, F
Ionization energy increases across a row
of the periodic table and decreases down
a column of the periodic table.
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7 | 78
Question
Sodium losing an electron is an ________
process and fluorine losing an electron is
an _______ process.
a)
b)
c)
d)
endothermic, exothermic
exothermic, endothermic
endothermic, endothermic
exothermic, exothermic
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7 | 79
Answer
c) endothermic, endothermic
Losing an electron from an atom requires
energy, which means this reaction is
endothermic.
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7 | 80
Question
Which of the following oxides are acidic?
a)
b)
c)
d)
e)
Na2O
CaO
N2O5
All of the above
None of the above
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7 | 81
Answer
c) N2O5
Most nonmetal oxides are acidic. Most metal
oxides are basic. Oxides of elements in the
periodic table near the transition between
metals and nonmetals may be amphoteric
oxides.
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7 | 82