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Study Guide for Content Mastery Chemistry: Matter and Change • Chapter 4 19
The Structure of the AtomThe Structure of the Atom
Section 4.1 Early Theories of MatterIn your textbook, read about the philosophers, John Dalton, and defining the atom.
For each statement below, write true or false.
1. Ancient philosophers regularly performed controlled experiments.
2. Philosophers formulated explanations about the nature of matter based ontheir own experiences.
3. Both Democritus and Dalton suggested that matter is made up of atoms.
4. Dalton’s atomic theory stated that atoms separate, combine, or rearrangein chemical reactions.
5. Dalton’s atomic theory stated that matter is mostly empty space.
6. Dalton was correct in thinking that atoms could not be divided intosmaller particles.
7. Dalton’s atomic theory stated that atoms of different elements combine insimple whole-number ratios to form compounds.
8. Dalton thought that all atoms of a specific element have the same mass.
9. Democritus proposed that atoms are held together by chemical bonds, butno one believed him.
10. Dalton’s atomic theory was based on careful measurements and extensiveresearch.
11. There are no instruments powerful enough to magnify atoms so that theycan be seen.
12. The smallest particle of an element that retains the properties of thatelement is called an atom.
STUDY GUIDE FOR CONTENT MASTERYCHAPTER 4
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Chapter Assessment Chemistry: Matter and Change • Chapter 4 19
The Structure of the AtomThe Structure of the Atom
Reviewing VocabularyMatch each definition in Column A with the term in Column B.
Column A Column B
1. Radiation deflected toward the positively charged plate
2. Atoms with the same number of protons but different numbers of neutrons
3. High-energy radiation that has no charge and no mass
4. The smallest particle of an element that retains the properties of that element
5. The weighted average mass of an element’s isotopes
6. The center-most part of an atom where the protons and neutronsare contained
7. Radiation deflected toward the negatively charged plate
8. The rays and particles emitted by radioactive material
9. Equal to 1/12 the mass of a carbon-12 atom
10. Ray of radiation traveling from the cathode to the anode
11. Process (not requiring energy) by which unstable nuclei lose energy
12. States that all matter is composed of atoms
13. Process whereby some substances spontaneously emit radiation
Compare and contrast each pair of related terms.
14. mass number, atomic number
15. nuclear reaction, nuclear equation
CHAPTER ASSESSMENTCHAPTER 4
a. atom
b. nucleus
c. atomic mass
d. isotopes
e. gamma ray
f. alpha radiation
g. beta radiation
h. atomic massunit
i. radiation
j. Dalton’s atomictheory
k. cathode ray
l. radioactivity
m. radioactivedecay
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Study Guide for Content Mastery Chemistry: Matter and Change • Chapter 4 21
Section 4.3 How Atoms DifferIn your textbook, read about atomic number.
For each statement below, write true or false.
1. The number of neutrons in an atom is referred to as its atomic number.
2. The periodic table is arranged by increasing atomic number.
3. Atomic number is equal to the number of electrons in an atom.
4. The number of protons in an atom identifies it as an atom of aparticular element.
5. Most atoms have either a positive or a negative charge.
Answer the following questions.
6. Lead has an atomic number of 82. How many protons and electrons does lead have?
7. Oxygen has 8 electrons. How many protons does oxygen have?
8. Zinc has 30 protons. What is its atomic number?
9. Astatine has 85 protons. What is its atomic number?
10. Rutherfordium has an atomic number of 104. How many protons and electrons does it have?
11. Polonium has an atomic number of 84. How many protons and electrons does it have?
12. Nobelium has an atomic number of 102. How many protons and electrons does it have?
In your textbook, read about isotopes and mass number.
Determine the number of protons, electrons, and neutrons for each isotope described below.
13. An isotope has atomic number 19 and mass number 39.
14. An isotope has 14 electrons and a mass number of 28.
15. An isotope has 21 neutrons and a mass number of 40.
STUDY GUIDE FOR CONTENT MASTERYCHAPTER 4
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22 Chemistry: Matter and Change • Chapter 4 Study Guide for Content Mastery
16. An isotope has an atomic number 51 and a mass number 123.
Answer the following question.
17. Which of the isotopes in problems 13–16 are isotopes of the same element? Identify theelement.
Write each isotope below in symbolic notation. Use the periodic table to determine theatomic number of each isotope.
18. neon-22 20. cesium-133
19. helium 21. uranium-234
Label the mass number and the atomic number on the following isotope notation.
22.
23.
In your textbook, read about mass of individual atoms.
Circle the letter of the choice that best completes the statement.
24. The mass of an electron is
a. smaller than the mass of a proton. c. a tiny fraction of the mass of an atom.
b. smaller than the mass of a neutron. d. all of the above.
25. One atomic mass unit is
a. 1/12 the mass of a carbon-12 atom.
b. 1/16 the mass of an oxygen-16 atom.
c. exactly the mass of one proton.
d. approximately the mass of one proton plus one neutron.
26. The atomic mass of an atom is usually not a whole number because it accounts for
a. only the relative abundance of the atom’s isotopes.
b. only the mass of each of the atom’s isotopes.
c. the mass of the atom’s electrons.
d. both the relative abundance and the mass of each of the atom’s isotopes.
Section 4.3 continued
STUDY GUIDE FOR CONTENT MASTERYCHAPTER 4
2412Mg
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Study Guide for Content Mastery Chemistry: Matter and Change • Chapter 4 23
Use the figures to answer the following questions.
27. What is the atomic number of osmium?
28. What is the chemical symbol for niobium?
29. What is the atomic mass of osmium?
30. What units is the atomic mass reported in?
31. How many protons and electrons does an osmium atom have? A niobium atom?
Calculate the atomic mass of each element described below. Then use the periodic tableto identify each element.
32.
33.
Osmium
76
Os190.2
Niobium
41
Nb92.906
Section 4.3 continued
STUDY GUIDE FOR CONTENT MASTERYCHAPTER 4
Isotope Mass (amu) Percent Abundance
63X 62.930 69.17
65X 64.928 30.83
Isotope Mass (amu) Percent Abundance
35X 34.969 75.77
37X 36.966 24.23
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Radioactivity and Nuclear Reactions 31
How do isotopes differ?
Directions: Most elements exist in nature as isotopes. Isotopes of an element are almost identical in their chemical properties and reactions. However, the nuclear properties of isotopes are different. Not only do isotopesdiffer in mass, but some may be radioactive. Using a periodic table, complete the information in the chart below.
Enrichment11
Mee
ting
Indi
vidu
al N
eeds
9Chapter
1. H
2. H
3. H
4. He
5. C
6. C
7. O
8. Sc
9. Co
10. Pb
11. Ra
12. Ra
13. U
14. U
Symbol Atomic numberNumber of
protonsMass number
Number of neutrons
11
21
31
42
126
146
188
4921
6327
21282
22288
22688
23592
23892
1
2 2
2821
1
3
12
14
18
63
212
222
226
235
238
1
Name Date Class
20 Properties of Atoms and the Periodic Table
Section 1 ■ Structure of theAtom
Section 2 ■ Masses of Atoms
Directions: Use the terms below to complete the following paragraphs about atoms , atomic mass, and isotopes. Terms may be used more than once.
six number electrons isotopes electron cloud
neutron(s) proton(s) mass quarks six protons
The electron has very little mass compared to the 1. ________________ or
2. ________________. The mass of the atom depends on the nucleus and how
many 3. ________________ and 4. ________________ it has. The sum of the
protons and neutrons is the mass 5. ________________ of an atom. The number
of neutrons in an atom can be found by subtracting the atomic number from the
6. ________________ number. The mass of the atom is so small that there is a
measure called the atomic 7. ________________ unit designated by amu.
8. ________________ and 9. ________________ make up the nucleus and are made up
of 10. ________________. There are 11. ________________ uniquely
different quarks. 12. ________________ are found in an area around the nucleus called
the 13. ________________. The nuclei of all atoms of a given element always have the
same number of 14. ________________. They will also have the same number of
15. ________________ around the nucleus. Some atoms may have more or fewer
16. ________________ than will other atoms of the same element. Atoms of the same
element with different numbers of neutrons are called 17. ________________. Every
atom of carbon must contain 18. ________________ but some contain six neutrons and
others have eight neutrons.
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Meeting Individual Needs
Directed Reading for
Content Mastery 18Chapter
28 Properties of Atoms and the Periodic Table
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Masses of Atoms
Directions: Answer the following questions on the lines provided.1. What are isotopes?
2. How do Boron-10 and Boron-11 differ?
3. What is the average atomic mass of an element?
4. Compare and contrast the atomic structure of the chlorine-35 and chlorine-37 isotopes.
5. Suppose that a newly discovered element called centium has three isotopes that occur innature. These are centium-200, centium-203, and centium-209. Assume that these isotopesoccur in equal amounts in nature. What will be the average atomic mass of this element?
Meeting Individual Needs
Reinforcement22 18Chapter
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Chapter Assessment Chemistry: Matter and Change • Chapter 4 21
Understanding Main Ideas (Part B)
For each description in Column A, write the letter of the matching symbol in Column B.
Column A Column B
1. Isotope in which the number of neutrons is six more than theisotope’s atomic number
2. Copper-63
3. Copper with seven neutrons more than its atomic number
4. Isotope that has one neutron more than its number of protons
5. Carbon with equal numbers of neutrons, protons, and electrons
6. Carbon with two more neutrons than its number of protons
7. Chromium with two more neutrons than its number of protons
8. Isotope in which the difference between the neutrons and numberof protons is 4
Answer the following questions.
9. Calculate the atomic mass of gallium (Ga). Gallium has two isotopes: 69Ga and 71Ga.69Ga has a relative abundance of 60.12% and an atomic mass of 68.9257 amu. 71Ga has arelative abundance of 39.88% and an atomic mass of 70.9249 amu. Show all your work.
10. Calculate the atomic mass of the element X. Then use the periodic table to identify theelement. Show all your work.
CHAPTER ASSESSMENTCHAPTER 4
a. 178O
b. 6329Cu
c. 126C
d. 5024Cr
e. 146C
f. 6529Cu
g. 5224Cr
h. 5424Cr
Isotope Mass (amu) Percent Abundance
27X 27.977 92.23
28X 28.976 4.67
29X 29.974 3.10
30 Radioactivity and Nuclear Reactions
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Nuclear ReactionsReinforcement44
Meeting Individual Needs
9Chapter
Energy2p2n
1p1n
1p1n ++
Energy
Energy
92p143n
n
n
n
n
56p85n
36p56n
1. The diagrams show two types of nuclear reactions: nuclear fission and nuclear fusion. Label thetype of reaction shown in each diagram in the space provided.
2. Circle the letter of the equation that correctly explains the nuclear reaction shown in the topdiagram.
a. H-2 + H-2 → H-4 c. H-1 + H-1 → H-2
b. H-2 + H-2 → He-4 d. H-1 + H-1 → He-2
3. Circle the letter of the equation that correctly explains the nuclear reaction shown in the bottom diagram.
a. 1 neutron + U-235 → Ba-141 + Kr-92 + 3 neutrons + energy
b. 1 neutron + U-238 → Ba-141 + Kr-92 + 4 neutrons
c. Ba-141 + Kr-92 → U-235 + 3 neutrons
d. Ba-141 + Kr-92 → U-238
4. What two elements are involved in the nuclear fusion reaction?
5. Label each atom in the fusion reaction with its correct symbol and isotope notation.
6. What three elements are involved in the fission reaction shown?
7. Label each atom in the nuclear fission reaction with its chemical symbol and its correct isotopenotation.
Directions: Use the diagrams below to complete the following activities.
�
�
�
�
Positive plate
HoleLead block
Radioactivesource
Gamma rays(no charge)
Zinc sulfidecoated screen
Betaparticles
(1� charge)
Alphaparticles
(2� charge)Negative plate
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24 Chemistry: Matter and Change • Chapter 4 Study Guide for Content Mastery
Section 4.4 Changes to the Nucleus—Nuclear ReactionsIn your textbook, read about radioactivity.
For each item in Column A, write the letter of the matching item in Column B.
Column A Column B
1. The rays and particles that are emitted by a radioactive material
2. A reaction that involves a change in an atom’s nucleus
3. The process in which an unstable nucleus loses energyspontaneously
4. Fast-moving electrons
In your textbook, read about types of radiation.
Use the diagram to answer the questions.
5. Which plate do the beta particles bend toward? Explain.
6. Explain why the gamma rays do not bend.
7. Explain why the path of the beta particles bends more than the path of the alpha particles.
Complete the following table of the characteristics of alpha, beta, and gamma radiation.
STUDY GUIDE FOR CONTENT MASTERYCHAPTER 4
a. nuclear reaction
b. beta radiation
c. radiation
d. radioactive decay
Radiation Type Composition Symbol Mass (amu) Charge
8. Alpha
9. 1/1840
10. High-energy electromagnetic radiation
Name: Date:
Use the diagram below to answer question 1.
1 The diagram above illustrates a nuclear reaction inwhich uranium-238 emits an alpha particle. Howmany protons and neutrons will the daughter nucleus have?
A 90 p and 144 n
B 92 p and 142 n
C 92 p and 150 n
D 94 p and 148 n
2 In his latest dig, Dr. Butrell found an abundance oflead (Pb) in some ancient artifacts. What is theatomic number of Pb?
A 80
B 81
C 82
D 83
Use the chart below to answer questions 3 and 4.
3 The chart shows isotopes of some common elements.Which property is used to name the isotopes?
A Atomic number
B Atomic mass
C Mass number
D Percent natural occurrence
4 The atomic mass of an element is the weightedaverage mass of the isotopes of that element. Basedon this definition, which of these does NOT showthe correct atomic mass for an element?
A Hydrogen: 1.008 amu
B Carbon: 12.011 amu
C Oxygen: 15.999 amu
D Copper: 63.017 amu
%abundance
99.9850.015
98.901.090.01
98.900.0380.200
69.1730.83
Element
hydrogen
carbon
oxygen
copper
Atomic#
1
6
8
29
Isotope
hydrogen-1hydrogen-2
carbon-12carbon-13carbon-14
oxygen-16oxygen-17oxygen-18
copper-63copper-65
Atomic massof isotope
1.01 amu2.01 amu
12.00 amu13.00 amu14.00 amu
15.99 amu17.00 amu18.00 amu
62.94 amu64.93 amu
uranium-238 nucleus(parent nucleus)
proton (p)neutron (n)
daughternucleus
helium-4 nucleus(alpha particle)
+ 2 p2 n
++ ++
+++
+
++++92 p
146 n
The Structure of the AtomCHAPTER 4
7
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Reviewing Chemistry: Mastering the TEKS Chemistry: Matter and Change
This question covers TEKS 6B. This question teststhe material that was covered in the textbook onpage 106.
This question covers TEKS 6B. This question teststhe material that was covered in the textbook onpage 100.
This question covers TEKS 6B. Thisquestion tests the material that wascovered in the textbook on page 104.
This question covers TEKS 3D. This question teststhe material that was covered in the textbook onpage 105.
Use the diagram below to answer question 5.
5 The diagram above shows the results of Rutherford’sexperiment in which he used a radioactive source to“shoot” alpha particles at a thin sheet of gold foil.Based on these results, what were Rutherford’sconclusions?
A Atoms are solid matter with positive andnegative charges scattered throughout.
B Atoms are solid, positively charged matter withnegatively charged electrons scatteredthroughout.
C Atoms are mostly empty space with small,dense, positively charged centers.
D Atoms are mostly empty space with small,dense, negatively charged centers.
6 The cathode ray tube is a key component of whichof the following revolutionary inventions?
A Automobile
B Fax machine
C Television
D Photocopier
Use the diagram below to answer question 7.
7 The diagram above shows how alpha, beta, andgamma rays are affected by two electrically chargedplates. Based on the paths the rays follow, what are therespective charges of alpha, beta, and gamma rays?
A negative, positive, none
B positive, negative, none
C negative, none, positive
D positive, none, negative
8 In the fourth century BC, Greek scholars rejectedDemocritus’s ideas about the atom. This rejectionwas most likely based on —
A experimentation
B government legislation
C religious beliefs
D the popularity of Aristotle’s ideas on nature
rays
raysrays
radioactive substancelead shield
- +
+
+
+
+
+
paths ofalpha particles
—nucleus of gold atom
alpha particle
8
CHAPTER 4 The Structure of the Atom, continued
Reviewing Chemistry: Mastering the TEKS
Copyright ©
Glencoe/M
cGraw
-Hill, a division of T
he McG
raw-H
ill Com
panies, Inc.
Name: Date:
Chemistry: Matter and Change
This question covers TEKS 6A. This question teststhe material that was covered in the textbook onpage 106.This question covers TEKS 3A. This question
tests the material that was covered in thetextbook on page 95.
This question covers TEKS 3C. Thisquestion tests the material that wascovered in the textbook on page 89.
This question covers TEKS 3C. This question teststhe material that was covered in the textbook onpages 92–93.