MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 3: ELEMENTS AND ATOMIC STRUCTURE
ATOMS AND ELEMENTS
WORKSHEET SOLUTIONS
1. This scientist discovered the electron.
1A. JJ Thomson
2. This scientist proposed the plum pudding model.
2A. JJ Thomson
3. This scientist disproved the plum pudding model.
3A. Ernest Rutherford
4. This scientist discovered the nucleus.
4A. Ernest Rutherford
5. This scientist coined the term “atom.”
5A. Democritus
6. This scientist first organized the periodic table.
6A. Mendeleev
7. Most of the atom’s mass and all of its __________ charge are contained in the __________.
7A. positive nucleus
8. The atom’s nucleus contains __________ and __________.
8A. protons neutrons
9. An atom with 16 protons, 17 neutrons and 18 electrons has a mass of __________ and a charge of
__________ and belongs to the element __________.
9A. 33 amu - 2 sulfur
10. Classify each of the following as a metal, a nonmetal, or a metalloid:
10a. Cl A. non metal
10b. K
A. metal
10c. Si
A. metalloid
10d. N
A. nonmetal
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CHEMISTRY
MR. SURRETTE
VAN NUYS HIGH SCHOOL
11. Determine the group or family for each of the following.
11a. F
11b. Ca
A. halogen
A. alkaline earth metals
11c. Li
A. alkali metals
11d. N
A. nonmetals
12. A positive ion is called a(n) __________ , while a negative ion is called a(n) __________.
A. cation anion
13. An iron isotope has 29 neutrons.
13a. What is the atomic symbol for iron?
A. Fe
13b. What is the Z value?
A. 26
13c. What is the A value?
A.
(1) A = Z + N
(2) A = 26 + 29
(3) A = 55
14. Ni-62 has how many protons and how many neutrons?
A. 28 protons 34 neutrons
15. Gallium has two naturally occurring isotopes: Ga-69 and Ga-71. Ga-71 is 6.11% abundant. The
atomic mass of gallium is 69.72 amu.
15a. Calculate the natural abundance of Ga-69.
A.
(1) Total mass of gallium must equal 100%.
(2) 100 – 6.11 = 93.89
(3) Natural abundance for Ga-69 is 93.89%
15b. Out of 10,000 gallium atoms, how many would be Ga-69 and Ga-71?
A. 611 Ga-71 and 9389 Ga-69
16. Which of the following elements is diatomic?
(a) C (b) He (c) Au (d) H
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CHEMISTRY
MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 3: ELEMENTS AND ATOMIC STRUCTURE
NUCLEUS WORKSHEET SOLUTIONS
1. A radioactive material initially has an activity of 1200 counts/sec. If six hours later it has an activity
of 300 counts/sec, what is its half life?
1A.
(1) 1200  600  300
(2) 2 half-lives have gone by, since each arrow represents one half-life.
(3) Let x = one half-life.
(4) Since the total time is 6 hours: 2x = 6 hours
(5) x = 3 hours
2. 88Ra-226 decays to 86Rn-222 by emitting what type of particle:
(A) beta
(B) proton
(C) gamma
(D) positron
(E) alpha
2A.
A= number of nucleons
Z = number of protons
(1) Parent particle:
A = 226
(2) Daughter particle: A = 222
(3) A = 4 Z = 2
(4) alpha particle
Z = 88
Z = 86
3. How does the daughter nucleus differ from the parent in the beta emission process:
(A) atomic mass increases by one
(B) atomic number increases by two
(C) atomic number increases by one
(D) atomic mass decreases by two
(E) atomic charge increases by two
4. What energy results when one hydrogen atom and one neutron are combined to form a deuterium
atom? (hydrogen 1.007825 u, neutron 1.009665 u, deuterium 2.014100 u)
4A.
Let mB = “mass before reaction”
Let mA = “mass after reaction”
(1) mB = 1 H + 1 n
(2) mB = 1.007825 u + 1.009665 u
(3) mB = 2.01749 u
(4) mA = 2H
(5) mA = 2.014100 u
(6) m = mB - mA
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CHEMISTRY
MR. SURRETTE
VAN NUYS HIGH SCHOOL
4A. continued…
(7) m = 2.01749 u – 2.014100 u
(8) m = 0.00339 u
(9) E = mc2
(10) E = (m)c2
(11) E = (0.00339 u)(931.5 MeV / 1u)
(12) E = 3.16 MeV
5. If there are 6 neutrons in C-12, how many neutrons are in C-14?
5A.
(1) A1 = Z + N1
(2) Z = A1 – N1
(3) Z = 12 – 6
(4) Z = 6 (number of protons in C)
(5) A2 = Z + N2
(6) N2 = A2 – Z
(7) N2 = 14 – 6
(8) N2 = 8 (number of neutrons in C-14)
6. What particle is emitted when 15P-32 decays to 16S-32?
(A) alpha
(B) beta
(C) neutron
(D) gamma
(E) proton
7. What is the Q-value for the reaction 9Be +   12 C + n? (m = 4.0026 u, mBe = 9.01218 u, mc =
12.0000 u, mn = 1.008665 u, and c2 = 931 MeV/u)
7A.
(1) mB = mBe +  m
mu4.0026 u
(3) mB = 13.01478 u
(4) mA = mc + mn
(5) mA = 12.0000 u + 1.008665 u
(6) mA = 13.008665 u
(7) m = mB – mA
(8) m = 0.006115 u
(9) E = (m)c2
(10) E = (0.006115 u)(931.5 MeV/ u)
(11) E = 5.69 MeV (Q-value)
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CHEMISTRY
MR. SURRETTE
VAN NUYS HIGH SCHOOL
8. Nuclear fusion involves combining the nuclei of:
(A) low atomic numbers
(B) metals
(C) non-metals
(D) noble gases
(E) high atomic numbers
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CHEMISTRY
MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 3: ELEMENTS AND ATOMIC STRUCTURE
QUIZ SOLUTIONS
1. These elements are somewhat good conductors of heat and electricity.
1A. metalloids
2. Group 1 elements of the periodic table are called the:
2A. alkali metals
3. Group 18 elements of the periodic table are called the:
3A. noble gases
4. This scientist discovered the electron.
4A. JJ Thomson
5. This scientist proposed the nuclear theory of the atom.
5A. Ernest Rutherford
6. This scientist developed the periodic table.
6A. Dmitri Mendeleev
7. Which of the following elements is diatomic?
7A. Iodine
8. An atom with 15 protons, 17 neutrons and 18 electrons has a mass of __________ and a charge of
__________ and belongs to the element __________.
8A. 32 amu - 3 phosphorus
9. A radioactive material initially has an activity of 1200 counts/sec. If six hours later it has an activity
of 600 counts/sec, what is its half life?
9A.
(1) 1200  600
(2) 1 half-life has gone by in 6 hours.
(3)  = 6 hours
10.
(A)
(B)
(C)
(D)
(E)
88
Ra-226 decays to 86Rn-222 by emitting what type of particle:
beta
proton
gamma
positron
alpha
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CHEMISTRY
MR. SURRETTE
VAN NUYS HIGH SCHOOL
11. Convert 302 K into oC
11A.
(1) Tc = T – 273
(2) Tc = 302 – 273
(3) Tc = 29
(4) Tc = 2.9 x 101 oC
12. Convert 302 K into oF
12A.
(1) Tc = T – 273
(2) Tc = 302 – 273
(3) Tc = 29 oC
(4) TF = (9/5) Tc + 32
(5) TF = (9/5) (29 oC) + 32
(6) TF = 84.2 oF
(7) TF = 8.42 x 101 oF
(8) TF = 8.4 x 101 oF
13. Convert 10.18 mg/mL into ng/L
13A.
10.18 mg x
1g
x 109 ng x 1000 mL
---------------------------------------1 mL
1000 mg
1g
1L
= 1.018 x 1010 ng/L
14. Sc
14A. metal
15. I
15A. nonmetal
16. Kr
16A. nonmetal
17. If there are 6 neutrons in N-13, how many neutrons are in N-14?
17A.
(1) A1 = Z + N1
(2) Z = A1 – N1
(3) Z = 13 – 6
(4) Z = 7 (number of protons in N)
(5) A2 = Z + N2
(6) N2 = A2 – Z
(7) N2 = 14 – 7
(8) N2 = 7 (number of neutrons in N-14)
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CHEMISTRY
MR. SURRETTE
VAN NUYS HIGH SCHOOL
18. Mg
18A. alkaline metals
19.
(A)
(B)
(C)
(D)
(E)
What particle is emitted when 15P-32 decays to 16S-32?
alpha
neutron
gamma
proton
beta
20. Xe
20A. noble gases
21. Na
21A. alkali metals
22. Argon (atomic number 18) has three isotopes:
Ar-36: 35.97 amu 0.34% relative abundance
Ar-38: 37.96 amu 0.07% relative abundance
Ar-40: 39.96 amu 99.59% relative abundance
Based on these three isotopes, compute the atomic mass of argon.
22A.
(1) A (Ar) = (35.97 x 0.0034) + (37.96 x 0.0007) + (39.96 x 0.9959)
(2) A (Ar) = 0.122298 + 0.002772 + 39.796164
(3) A (Ar) = 39.921234 amu
(4) A (Ar) = 39.92 amu
23. What is the Q-value for the reaction 9Be +   12 C + n?
(m = 4.0026 u, mBe = 9.01218 u, mc = 12.0000 u, mn = 1.008665 u, and c2 = 931.5 MeV/u)
23A.
(1) mB = mBe +  m
mu4.0026 u
(3) mB = 13.01478 u
(4) mA = mc + mn
(5) mA = 12.0000 u + 1.008665 u
(6) mA = 13.008665 u
(7) m = mB – mA
(8) m = 0.006115 u
(9) E = (m)c2
(10) E = (0.006115 u)(931.5MeV /u)
(11) E = 5.69 MeV (Q-value)
24. C-12 has a natural abundance of 98.89%. Out of a random sample of 10,000 carbon atoms, how
many would not be C-12?
24A. 111
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CHEMISTRY