Download Unit Review 2/22

Unit 03: Test Review
Atoms and Elements
Key Term
Definition
A. Element
_____ 1. The number of protons and neutrons of an atom.
B. Atom
_____ 2. The smallest particle of an element.
C. Atomic Number
_____ 3. A primary substance that cannot be broken down into simple
substances.
D. Mass Number
_____ 4. An atom of an element that has a different number of neutrons
than another atom of the same element.
E. Isotope
_____ 5. The number of protons in an atom.
Chemical Symbols
Write the symbol for each of the following elements:
1. _______ carbon
6. _______ iron
2. _______ phosphorus
7. _______ oxygen
3. _______ iodine
8. _______ sulfur
4. _______ lead
9. _______ calcium
5. _______ copper
10. _______ neon
11. _______ sodium
12. _______ nitrogen
13. _______ potassium
14. _______ gold
15. _______ chlorine
Write the names of the elements represented by each of the following symbols:
1. Mg
_______________ 7. K _______________
2. Au
_______________ 8. F
_______________
3. Cu
_______________ 9. Be _______________
4. Ag
_______________ 10. Br _______________
5. Zn
_______________ 11. Al _______________
6. Ba
_______________ 12. Li _______________
The Periodic Table
Indicate whether the following are in the same group (G), period (P) or neither (N)
1. _____ Li, C and O
5. _____ Br, Cl and F
2. _____ Al, Si and Cli
6. _____ C. N and O
3. _____ Mg, Ca and Ba
7. _____ C, S, and Br
4. _____ Li, Na and K
8. _____ K, Ca and Br
Complete the list of elements, group numbers and period numbers for the following table:
Element/Symbol
Group Number
Period Number
2A
3
5A
2
4A
5
1A
6
Silicon/Si
Aluminum/Al
Identify each of the following as a metal (M) or nonmetal (NM)
1. _____ C
2. _____ C
3. _____ N
4. _____ Ca
5. _____ Fe
6. _____ Zn
7. _____ K
8. _____ Ag
9. _____ Al
10. _____ Mg
Place the following atoms into the correct group of elements: K, Cl, He, Fe, Mg, Ne, Li, Cu and
Br
1. Halogens
________________________________________________
2. Noble Gases
________________________________________________
3. Alkali Metals
________________________________________________
4. Alkaline Earth Metals ________________________________________________
5. Transition Metals
________________________________________________
The Atom
True/False
1. _____ All matter is composed of atoms.
2. _____ All atoms of an element are identical.
3. _____ Atoms combine to form compounds.
4. _____ Most of the mass of the atom in the nucleus.
Key Term
Definition
A. Proton
_____ 1. Found in the nucleus of an atom
B. Neutron
_____ 2. Found outside the nucleus
C. Electron
_____ 3. The small, dense center of an atom
D. Nucleus
_____ 4. Has a (-1) charge
_____ 5. Has a mass of 1 amu
_____ 6. Is neutral
Atomic Number and Mass Number
Give the number of ​protons ​in each of the following neutral atoms:
1. _____ An atom of Carbon
2. _____ An atom of the element with the atomic number 15
3. _____ An atom with a mass number of 40 and an atomic number 19
4. _____ An atom with 9 neutrons and a mass number of 19
5. _____ A neutral atom that has 18 electrons
Find the number of neutrons in each of the following atoms:
1. _____ A mass number of 42 and atomic number 20.
2. _____ A mass number of 10 and 5 protons.
3. _____ 30​
​ 14 ​Si
4. _____ A mass number of 9 and atomic number 4
5. _____ A mass number of 22 and 10 protons
6. _____ A zinc atom with a mass number of 66
Symbol
Atomic
Number
Mass
Number
Protons
12
12
20
55
45
35
50​
22
29
35
120​
Neutrons
17
Sn
Identify the sets of atoms that are isotopes:
1. 20 ​10​ X
2. 20​
​ 11​ X
3. 21​
​ 11​ X
4. 19​
​ 10​ X
5. 19​
​ 9​ X
Electrons
Average Atomic Miss
Calculations
1. Rubidium is a soft, silvery-white metal that has two common isotopes, 85​
​ Rb and 87​
​ Rb. If
the abundance of ​85​Rb is 72.2% and the abundance of 87​
​ Rb is 27.8%, what is the
average atomic mass of rubidium?
2. Uranium is used in nuclear reactors and is a rare element on earth. Uranium has three
common isotopes. If the abundance of 234​
​ U is 0.01%, the abundance of 235​
​ U is 0.71%,
and the abundance of 238​
​ U is 99.28%, what is the average atomic mass of uranium?
3. Titanium has five common isotopes: 46​
​ Ti (8.0%), 47​
​ Ti (7.8%), ​48​Ti (73.4%), 49​
​ Ti (5.5%),
50​
Ti (5.3%). What is the average atomic mass of titanium?
4. Calculate the average atomic mass of sulfur if 95.00% of all sulfur atoms have a mass of
31.972 amu, 0.76% has a mass of 32.971amu and 4.22% have a mass of 33.967amu.
5. Calculate the average atomic mass of bromine. One isotope of bromine has an atomic
mass of 78.92amu and a relative abundance of 50.69%. The other major isotope of
bromine has an atomic mass of 80.92amu and a relative abundance of 49.31%.
6. Naturally occurring chlorine that is put in pools is 75.53 percent 35​
​ Cl (mass = 34.969
37​
amu) and 24.47 percent ​ Cl (mass = 36.966 amu). Calculate the average atomic mass.
Conceptual Question: Copper has two naturally occurring isotopes: 63​
​ Cu and 65​
​ Cu. If that is the
case, why is that average atomic mass of copper listed as 63.35 on the periodic table?
Nuclear Radiation
1. What is nuclear radiation?
2. In nuclear medicine, iodine-125 is used for detecting a tumor in the thyroid. What does
the number 125 used in the name indicate?
3. How does nuclear fission differ from nuclear fusion?
Key Term
Definition
A. radioactive
nucleus
_____ 1. A particle identical to a helium nucleus produced in a
radioactive nucleus.
B. Half-life
_____ 2. The time required for one-half of a radioactive sample of
undergo radioactive change
C. curie
_____ 3. A unit of radiation that measures the activity of a sample
D. nuclear fission
_____ 4. A process in which large nuclei split into smaller nuclei with the
release of energy
E. alpha particle
_____ 5. A nucleus that spontaneously emits radiation
Radioactivity
Key Term
Definition
A. 18​
​ 8​O
_____ 1. Symbol for a beta particle
B. ɣ
_____ 2. Symbol for an alpha particle
C. Radioactive
isotope
_____ 3. An atom that emits radiation
D. 4​​ 2​He
_____ 4. Symbol for an atom of oxygen
E. 𝛽
_____ 5. Symbol for gamma radiation
(1) Describe methods that you can use to limit the amount of radiation you would receive if
you regularly work with radioactive substances in your profession.
(2) Which type(s) of radiation (alpha, beta, gamma) would each of the following shielding
materials protect you from?
(a) _______________ clothing
(d) _______________ skin
(b) _______________ paper
(e) _______________ concrete
(c) _______________ lead wall
Nuclear Equations
(1) 66​29​Cu → 66​
​ 30​Zn + ______
(2) 238​
​ 92​U → 4​​ 2​He + ______
(3) 24​
​ 11​Na → 0​​ -1​e + ______
(4) ______ → 30​
​ 14​Si + 0​​ -1​e
(5) 40​
​ 20​Ca + ______ → 40​
​ 19​K + 1​​ 1​H
(6) 27​
​ 13​Al + 1​​ 0​n → 24​
​ 11​Na + ​______
(7) 10​
​ 5​B + 1​​ 0​n → 4​​ 2​He + ______
(8) 23​
​ 11​Na + ______ → 23​
​ 12​Mg + ​1​0​n
(9) 197​
​ 79​Au + 1​​ 1​H → ______ + 1​​ 0​n
Half-Lives
(1) Supposed you have an 80-mg sample of iodine-125. If iodine-125 has a half-life of 60
days, how many mg are radioactive
(a) After one half-life?
(b) After two half-lives?
(c) After 240 days?
(2) 99​
​ Tc has a half-life of 6 hours. If a technician picked up a 16 mg sample at 8AM, how
much of the radioactive sample remained at 8PM on the same day?
(3) Phosphorus-32 as a half-life of 14 days. How much of the 240-mg sample will be
radioactive after 56 days?
(4) Iodine-131 has a half-life of 8 days. How many days will it take for 80-mg of I-131 to
decay to 5-mg?
(5) Suppose a group of archaeologists digs up some pieces of a wooden boat at an ancient
site. When a sample of the wood is analyzed for C-14, scientists determine that 12.5%
(or ⅛) of the original amount of C-14 remains. If the half-life of carbon-14 is 5730 years,
how long ago was the boat made?
(6) Use this graph to answer the following questions:
(7)
(a) What is the half life of this substance?
(b) How much remains after 3 half-lives?
Practice Test Questions on Nuclear Chemistry
(1) The correctly written symbol for at atom of sulfur is
(a) 30​
​ 16​S
(b) 14​
​ 30​S
(c) 30​
​ 16​S
(d) 30​
​ 16​S
(e) ​16​30​S
(2) Alpha particles are composed of
(a) Protons
(c) neutrons
(e) electrons
(b) protons and electrons
(d) protons and neutrons
(3) Gamma radiation is the type of radiation that
(a) Originates in the electron shells
(b) Is most dangerous
(c) Is least dangerous
(d) Is the heaviest
(e) Goes the shortest distance
(4) The charge on an alpha particle is
(a) (-1)
(b) (+1)
(c) (-2)
(d) (+2)
(e) (+4)
For questions 5-9, select from the following:
(a) 0​​ -1​X
(b) 4​​ 2​He
(c) 1​​ 1​X
(5) An alpha particle
(6) A Beta particle
(7) A Gamma Ray
(8) A proton
(9) A neutron
(d) 1​​ 0​X
(e) ​0​0​X
(10) Shielding from gamma rays is provided by
(a) skin (b) paper
(c) clothing
(d) lead
(e) air
(11) The radioisotope iodine-131 is used as a radioactive tracer for studying thyroid gland
activity. The symbol for iodine-131 is
(a) I
(b) ​131​I
(c) ​131​52​I
(d) 53​
​ 131​I
(e) ​78​53​I
(12) When an atom emits an alpha particle, its atomic mass will
(a) Increase by 1
(b) increase by 2
(c) increase by 4
(d) decrease by 4 (e) will not change
(13) When a nucleus emits a beta particle, the atomic number of the new nucleus
(a) Increases by 1
(b) increases by 2
(c) decreases by 1
(d) decreases by 2
(e) will not change
(14) What a nucleus emits a gamma ray, the atomic number of the new nucleus
(b) Increases by 1
(b) increases by 2
(c) decreases by 1
(d) decreases by 2
(e) will not change
For questions 15-18, select the particle that best completes each equation
(a) neutron
(b) alpha particle
(c) beta particle
(d) gamma ray
126​
126​
(15) ​ 50​Sn → ​ 51​Sb + _____
(16) 69​
​ 30​Zn
→ 69​
​ 31​Ga + _____
(17) 99​
​ 43​Tc
→ 99​
​ 43​Tc + _____
149​
(18) ​ 62​Sm → 145​
​ 60​Nd + _____
(19) What symbol completes the following reaction?
14​
1​
1​
7​N + ​ 0​n → _____ + ​ 1​H
(a) 15​
​ 8​O
(b) 15​
​ 6​C(c) 14​
​ 8​O
(d) 14​
​ 6​C(e) 15​
​ 7​N
(20) To complete this nuclear equation, you need to write:
54​
57​
1​
26​Fe + _____ → ​ 28​Ni + ​ 0​n
(a) alpha particle (b) beta particle (c) gamma (d) neutron
(e) proton
(21) The time required for a radioisotope to decay is measured by its
(a) Half-life
(b) protons
(c) activity
(d) fusion
(e) radioisotope
(22) Oxygen-15 used in PET imaging has a half-life of 2 min. How many half-lives have
occurred in the 10 minutes it takes to prepare the sample?
(a) 2
(b) 3
(c) 4
(d) 5
(e) 6
(23) Iodine-131 has a half-life of 8 days. How long will it take for a 160-mg sample to decay to
10-mg?
(a) 8 days
(b) 16 days
(c) 32 days
(d) 40 days
(e) 48 days
(24) Phosphorus-32 has a half-life of 14 days. .After 28 days, how many mg of a 100-mg
sample will still be radioactive?
(a) 75 mg
(b) 50 mg
(c) 40 mg
(d) 25 mg
(e) 12.5 mg
(25) The splitting of a large nucleus to form smaller particles accompanied by a release of
energy is called
(a) Radioisotope (b) fission
(c) fusion
(d) rem
(e) half-life
(26) The process of combining small nuclei to form larger nuclei is
(a) Radioisotope (b) fission
(c) fusion
(d) rem
(e) half-life