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Chemistry Honors
Unit 2 Practice Test
Name _____________________________
1) The smallest particle of an element that retains the properties of that element
is the:
a) cell
b) proton
c) electron
d) neutron
e) none of the above
2) Which of the following is not a part of Dalton’s atomic theory?
a) All elements are composed of atoms.
b) The positive charge of the atom is located in a small, centralized nucleus
c) Atoms of the same element are identical.
d) Chemical reactions occur when atoms are separated, joined, or rearranged.
3) When Rutherford shot alpha particles at the gold foil, most of the alpha particles:
a) passed right through the foil without being deflected
b) were deflected at least 30 off their original path
c) were deflected at least 90 off their original path
d) bounced back off the foil
e) became embedded in the gold foil
4) Rutherford's experiment with alpha particle scattering by gold foil established that
a) protons are not evenly distributed throughout an atom.
b) electrons have a negative charge.
c) electrons have a positive charge.
d) atoms are made of protons, neutrons, and electrons.
e) protons are 1840 times heavier than electrons.
5) What determines the identity of an atom?
a) atomic mass
b) atomic number
c) number of neutrons
d) mass number
e) none of the above
6) The number of electrons in a neutral atom:
a) is found by adding together the number of electrons and protons.
b) is found by subtracting the number of neutrons from the number of protons.
c) is found by subtracting the number of protons from the mass number.
d) is found by adding the mass number to the number of protons.
e) is the same as the atomic number of the atom.
7) The number 65 in the name copper-65 represents:
a) the atomic number.
b) the number of neutrons.
c) the sum of the protons and electrons.
d) the atomic mass
e) none of the above
8) Which of these statements is true?
a) Protons have a positive charge.
b) Electrons are negatively charged and are nearly massless.
c) The nucleus of an atom is positively charged and has a very high density
d) nearly all of the mass of an atom is located in the nucleus
e) all of the above are true.
9) An atom of an element with atomic number 80 and mass number 180
contains:
a) 80 protons, 80 electrons, and 180 neutrons
b) 80 protons, 80 electrons, and 100 neutrons
c) 100 neutrons, 180 protons, and 180 electrons
d) 80 neutrons, 80 protons, and 80 electrons
e) none of the above
10) What percentage of the mass of a chromium-52 atom is contributed by its protons?
a)
b)
c)
d)
e)
6%
22 %
46 %
54 %
100 %
11) Most sodium atoms probably have ___ neutrons.
a) 11
b) 23
c) 12
d) 32
e) 22
12) A carbon atom with 8 neutrons in its nucleus would be called:
a) carbon-6
b) carbon-8
c) carbon-12
d) carbon-14
13) How many protons would a Gold-197 atom have?
a) 196
b) 197
c) 117
d) 118
e) carbon-18
e) none of these
14) How many electrons are in a magnesium ion (Mg+2)?
a) 10
b) 12
c) 14
d) 24
15) An ion with 16 protons and 18 electrons would be:
a) S+2
b) S-2
c) Ar-2
d) Ar+2
e) none of these
16) If E is the symbol for an element, which two of the following symbols represent isotopes of the same element?
1)
30
20
E
a) 1 and 2
2)
20
10
E
b) 3 and 4
3)
21
10
E
c) 1 and 4
4)
30
21
E
d) 2 and 3
17) A tritium atom has:
a) three protons, three neutrons, three electrons
b) three protons, zero neutrons, three electrons
c) one proton, three neutrons, one electron
d) one proton, two neutrons, one electron
e) none of the above
18) Most hydrogen atoms are the isotope _______________ and have ___ neutrons.
a) Hydrogen-1, 0
b) Hydrogen-2, 1
c) Hydrogen-3, 3
d) Hydrogen-1, 1
e) Hydrogen-2, 1
19) Isotopes of an element have different ______________ .
a) atomic numbers
b) numbers of neutrons
c) mass numbers
d) number of protons
e) both (b) and (c) are correct
20) Ions of the same element (such as 56Fe+2 and 56Fe+3) would differ by:
I. the number of protons
II. the number of neutrons
III. the number of electrons
IV. the atomic number
V. their mass number
VI. their charge
(a) I and IV
(b) II and V
(c) I and V
21) An atom with 12 protons and 13 neutrons is called:
a) aluminum-12
b) magnesium-13
c) aluminum-13
d) magnesium-25
e) none of the above
(d) III and VI
22) What is the mass number of Uranium-235?
a) 92
b) 146
c) 235
d) 238
e) none of these
23) Which one of the following statements is true?
C and 12C have the same number of neutrons
12
B and 12C are isotopes of each other because their mass numbers are the
same
32 -2
c) S has the same number of protons as 40Ar
d) 40Ca and 42Ti have the same mass number
e) 38Ar and 39K+ have the same number of electrons and neutrons
a)
b)
13
24) A 40Ca+2 ion has
a)
b)
c)
d)
e)
20 protons, 20 neutrons, and 18 electrons
22 protons, 20 neutrons, and 20 electrons
20 protons, 22 neutrons, and 18 electrons
22 protons, 18 neutrons, and 18 electrons
20 protons, 20 neutrons, and 22 electrons
25) The numbers of protons, neutrons, and electrons in 127I- is:
a)
b)
c)
d)
e)
52 p, 128 n, 53 e
53 p, 127 n, 54 e
53 p, 127 n, 52 e
53 p, 74 n, 54 e
53 p, 74 n, 52 e
26) Which of the following has 45 neutrons, 35 protons, and 36 electrons?
a)
80
Hg
b)
103
Rh-
c)
80
Br+
d)
71
Lu-
e) none of these
27) What isotope of carbon serves as the basis for the amu?
a)
12
C
b)
13
C
c)
14
C
d)
16
C
e)
24
C
e)
24
C
28) What isotope of carbon serves as the basis for carbon dating?
a) 12C
b) 13C
c) 14C
d)
29) What isotope results from α-decay of lead-210?
a) bismuth-210
b) mercury-206
16
C
c) thallium-210
d) lead-210
c) thallium-210
d) lead-210
30) What isotope results from β-decay of lead-210?
a) bismuth-210
b) mercury-206
31) What isotope results from γ-decay of lead-210?
a) bismuth-210
b) mercury-206
c) thallium-210
d) lead-210
32) What isotope results from positron emission of lead-210?
a) bismuth-210
b) mercury-206
c) thallium-210
d) lead-210
33) If a radioactive substance has a half life of 5.00 days, what percentage of the
substance remains after 20.0 days?
a) 50.0%
b) 25.0%
c) 12.5%
d) 6.25%
e) 3.13%
34) Consider 80 grams of a radioactive substance with a half-life of 10 minutes. Which
graph below best describes how the mass of the substance will vary with time?
(b)
(c)
90
90
80
80
80
70
70
70
60
50
40
30
Mass (grams)
90
Mass (grams)
Mass (grams)
(a)
60
50
40
30
60
50
40
30
20
20
20
10
10
10
0
0
0
10
20
30
Time (minutes)
0
0
10
20
30
40
50
Time (minutes)
0
10
20
30
35) What nuclear process will release energy for elements lighter than iron?
a) fusion
b) fission
36) What nuclear process is used in nuclear power plants?
a) fusion
b) fission
40
Time (minutes)
50
60
Matching: Each answer can be used more than once
A) α particle
B) Fe
C) gamma radiation
D) positron
E) 01 n
F) francium, Fr
G) β particle
H) carbon-12
1) _____ particle with virtually no mass
and a charge of +1
2) _____ particle with virtually no mass
and a charge of -1
3) _____ has a charge of +2
4) _____ is a radioactive element
5) _____ has absolutely no mass
6) ____ has no charge, but has a mass of about 1 amu
7) ____ cut-off element between fusion and fission
8) ____ has a mass of about 4 amu
9) ____ 1/12th the mass of this isotope is 1 amu (definition)
Problems:
1) Ruthenium consists of seven isotopes, with their masses and natural abundances
shown below:
Ruthenium-96
Ruthenium-98
Ruthenium-99
Ruthenium-100
Ruthenium-101
Ruthenium-102
Ruthenium-104
95.908 amu
97.905 amu
98.906 amu
99.904 amu
100.906 amu
101.904 amu
103.905 amu
5.526 %
1.886 %
12.71 %
12.61 %
17.01 %
31.62 %
18.72 %
Using this information, calculate the atomic mass of ruthenium.
2) The element chromium exists in nature in four isotopes. The abundances and masses
of each isotope of three of the isotopes are given below. Given that the atomic mass
of chromium is 51.9961 amu, calculate the percent abundance and mass of the fourth
isotope, and give its symbol.
Isotope
52
Cr
53
Cr
54
Cr
?
Mass (amu)
51.94051
52.94065
53.93888
?
% Abundance
83.789
9.501
2.365
?
3) A proton has a mass of 1.00728 amu, while a neutron has a mass of 1.00867 amu.
The electron has a very small mass of 0.00055 amu. Given this information, calculate
the mass defect of a zinc-64 atom (64Zn), which has a mass of 63.92914 amu. Where
does the “missing mass” go?
4) Consider the isotope Radium-226
(a) Calculate the number of protons, neutrons and electrons for this isotope, and
calculate the ration of neutrons/protons.
(b) Show this isotope undergoing α-decay.
(c) Show this isotope undergoing β-decay.
(d) Show this isotope undergoing positron emission.
(e) Show this isotope undergoing electron capture.
(f) Which process or processes are likely to occur for this isotope and why?
5) For each of the following pair of isotopes, one is radioactive and the other isn’t.
Circle the radioactive isotope, and predict which type(s) of radiation the isotope is
likely to undergo.
(a)
12
(b)
200
N or
14
Hg or
N
230
U
(c) deuterium or tritium
(d) tungsten-186 or tungsten-188
(e)
190
82
Pb or
206
82
Pb
6) Consider the graph below, which shows the decay of 60.0 grams of a radioactive
isotope:
Mass of Radioactive
isotope (g)
The Effect of Time on Mass of
Radioactive Sample
70
60
50
40
30
20
10
0
0
10
20
30
Time (hours)
(a) What is the half-life of the isotope?
(b) How many hours would it take for only 3.75 grams of the sample to remain?
(c) How many grams of the radioactive sample would be left after 2.00 days?
Answers to Chapter 3 and 19 Review
Multiple Choice
1.E
2. B
3. A
4. A
5. B
6. E
7. E
8. E
9. B
10. C
11. C 12. D 13. E 14. A 15. B 16. D 17. D 18. A 19. E 20. D
21. D 22. C 23. E 24. A 25. D 26. E 27.A 28. C
29. B 30. A
31. D 32. C 33. D 34. C 35. A 36. B
Matching
1. D
2. G
3. A
4. F
5. C
6. E
7. B
8. A
9. H
Problems
1) 101.15 amu
2) 50Cr, 49.95 amu, 4.345 %
3) 0.60 amu, goes into energy to hold nucleus together
4) (a) 88 protons, 88 electrons, 138 neutrons (n/p ratio = 1.57)
(b) 226Ra → 42 He + 222Rn
(c) 226Ra → 01 e + 226Ac (n/p ratio = 1.54)
(d) 226Ra → 01 e + 226Fr
(e) 226Ra + 01 e → 226Fr + 00 γ (Gamma radiation always occurs with e- capture)
(f) Alpha decay is likely because it will reduce the number of protons by 2;
Beta-decay is also likely to occur b/c this process reduces n/p ratio closer to 1.5
5) (a) 12N, electron capture and/or positron emission
(b) 230U, alpha decay
(c) tritium, beta decay
(d) tungsten-188, beta decay
(e) 190
82 Pb, electron capture and/or positron emission
6) (a) 8 hours (b) 32 hours (c) 0.938 g