4UVEFOU &EJUJPO $PNQBOJPO /PUFCPPL · 2019. 12. 8. · plants grow taller when they receive more sunlight. Identify an independent variable and a dependent variable for this investigation

Grade 8

Cover Image: light echo NASA/ESA/Hubble Heritage Team (STScI/AURA)

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ContentsUsing Your Student Edition Companion Notebook vi

Unit 1 The Nature of ScienceLesson 1 What Is Science? 1

STEM Engineering and Technology 4

Lesson 2 Scientific Knowledge 6

Lesson 3 Scientific Investigations 9

Think Science 12

Lesson 4 Science and Society 13

Unit Review 17

Unit 2 Measurement and DataLesson 1 Representing Data 21

Do the Math 24

Lesson 2 Scientific Tools and Measurement 25

Unit Review 29

Unit 3 Introduction to ChemistryLesson 1 The Atom 33

Lesson 2 The Periodic Table 36

Lesson 3 Electrons and Chemical Bonding 39

Lesson 4 Chemical Reactions 41

Think Science 44

Unit Review 47

Unit 4 Forces and MotionLesson 1 Matter in Motion 51

Lesson 2 Balanced and Unbalanced Forces 54

Lesson 3 Newton’s Laws of Motion 57

Unit Review 61

iiiContents

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Unit 5 The Earth-Moon-Sun SystemLesson 1 Earth’s Days, Years, and Seasons 65

Lesson 2 Moon Phases and Eclipses 67


Lesson 3 Earth’s Tides 71

Unit Review 75

Unit 6 The UniverseLesson 1 Structure of the Universe 79

Do the Math 82

Lesson 2 Stars 83

Lesson 3 The Life Cycle of Stars 85

Lesson 4 Observing the Universe 88

Lesson 5 The Origin of the Universe 91

Unit Review 95

Unit 7 Processes that Shape EarthLesson 1 The Theory of Plate Tectonics 99

Lesson 2 Plate Tectonics and Landforms 102

Lesson 3 Weathering, Erosion, and Deposition 105

Think Science 108

Lesson 4 Topographic Maps 109

Lesson 5 Images of Earth’s Surface 112

Unit Review 117

Unit 8 Earth’s Oceans and AtmosphereLesson 1 Wind in the Atmosphere 121

Lesson 2 Ocean Currents 124

Lesson 3 Global Weather Patterns 127


Lesson 4 Weather Maps and Weather Prediction 132

Unit Review 137

iv Contents

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Unit 9 EcosystemsLesson 1 Ecosystem Ecology 141


Lesson 2 Ecology of Terrestrial Ecosystems 146

Do the Math 148

Lesson 3 Ecology of Freshwater and Estuary Ecosystems 149

Lesson 4 Ecology of Marine Ecosystems 152

Lesson 5 Environmental Changes and Populations 155

Unit Review 159

vContents

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Quick Labs

• The Importance of Replication

• Improving an Electromagnet

Exploration Lab

• Road Safety

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Lesson

Scientific Investigations

ESSENTIAL QUESTION

How are scientific investigations conducted?By the end of this lesson, you

should be able to summarize the

processes and characteristics

of different kinds of scientific

investigations.

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Superconducting magnet assemblies,

such as the one shown here, help to

guide charged particles moving at almost the speed of light. Scientists study

the colliding particles to investigate the

nature of matter and energy.

4 Identify This list contains the vocabulary

terms you’ll learn in this lesson. As you

read, circle the definition of each term.

Vocabulary Terms

• experiment • dependent variable

• observation • data

• hypothesis • control

• variable

• independent variable

3 Synthesize The word experiment comes from

the Latin word experiri, meaning “to try.”

What do you think the meaning of the word

experiment is?

Active Reading

1 Evaluate Check T or F to show whether you

think each statement is true or false.

T FEvery scientific investigation is

an experiment.

You could do an experiment to

see if eating breakfast helps

students raise their grades.

Scientists need fancy

instruments to do experiments.

Scientists must repeat an

experiment for it to be useful.

2 Infer What do you think the scientists who

gathered the data for this graph were studying?Engage Your Brain

Answers for 1–3 should represent students’

current thoughts, even if incorrect.

1. F; T; F; T

2. They were studying the climate of Minne-

apolis.

3. Sample answer: An experiment is a pro-

cedure used by scientists to try out pos-

sible answers to questions or problems.

4. Students’ annotations will vary.

8.2A plan and implement comparative

and descriptive investigations by making

observations, asking well-defined questions, and

using appropriate equipment and technology

8.2B design and implement comparative

and experimental investigations by making

observations, asking well-defined questions,

formulating testable hypotheses, and using

appropriate equipment and technology

8.2D construct tables and graphs, using

repeated trials and means, to organize data and

identify patterns

32

33Lesson 3 Scientific Investigations

Unit 1 The Nature of Science

3

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Scientific Investigations (p. 32)

Lesson 31 Evaluate Check T or F to show whether you think each statement is true or false.

T F

Every scientific investigation is an experiment.You could do an experiment to see if eating breakfast helps students raise their grades.

Scientists need fancy instruments to do experiments.Scientists must repeat an experiment for it to be useful.

2 Infer What do you think the scientists who gathered the data for this graph were studying?

3 Synthesize The word experiment comes from the Latin word experiri, meaning “to try.” What do you think the meaning of the word experiment is?

5 Explain Why should hypotheses be testable?

6 Infer Write a hypothesis offering a possible explanation of what will happen to the plant shown in the photo in the Student Edition.

7 Apply Suppose you want to test the hypothesis that plants grow taller when they receive more sunlight. Identify an independent variable and a dependent variable for this investigation.

10 Apply Give another example of a scientific investigation that would require both observation and experiments.

8.2A; 8.2B; 8.2D

9Lesson 3 Scientific Investigations

Unit 1

What is not included in this Companion Notebook?Some questions in the Student Edition are not included in this notebook. Questions that would require you to underline words or draw on images in the Student Edition are not repeated in the Companion Notebook. Also not included are activities that require research outside the book, such as Think Outside the Book questions and questions from Why It Matters sections.

Using Your Student Edition Companion NotebookUse this Companion Notebook to write answers to questions that appear in the print or digital Student Edition. First, find your assigned lesson in the print or digital Student Edition. Then, use the Table of Contents at the front of this notebook (pages iii – v) to find the pages that correspond to the Student Edition lesson. Work with the Student Edition and Companion Notebook side by side.

What is included in this Companion Notebook?Most numbered questions and activities from the Student Edition are included in this notebook. All Lesson Review pages and Unit Review pages are reproduced exactly from the Student Edition. Plus, all You Try It! pages from Think Science, STEM Engineering and Technology, and Do the Math unit activities are included exactly as they appear in the Student Edition so that you can practice new skills.

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vi Using Your Student Edition Companion Notebook

Name: Date: Class:

Lesson

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1 Identify Read over the following vocabulary terms. In the spaces provided, place a + if you know the term well, a ~ if you have heard the term but are not sure what it means, and a ? if you are unfamiliar with the term. Then, write a sentence that includes the word you are most familiar with.

atom

electron

neutron

proton

nucleus

Sentence using known word:

2 Compare Use the figure shown in the Student Edition to answer the questions below. Check T or F to show whether you think each statement is true or false.

T F

Electrons move in orbits in the same way planets orbit the sun.

If this were a model of the atom, the nucleus would be in the same place as the sun.

3 Apply Use context clues to write your own definition for the words theory and revise.

Example Sentence: The scientist developed a theory to explain the structure of the atom.

theory:

Example Sentence: As scientists learned new information about atoms, they had to revise the model of the atom.

revise:

5 Describe Who was Democritus?

6 Analyze Look at the picture in the Student Edition. What can you infer about atoms from this image? What can’t you infer from the image?

8 Model Describe how you would show J. J. Thomson’s model of the atom using small beads and clay.

The Atom (p. 112)18.5A; 8.5B

33Lesson 1 The Atom

Unit 3

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9 Analyze Today’s model of the atom looks different from the models that came before it. Why has the model of the atom changed?

11 Summarize Complete the following table with information about the parts of the atom.

Part of the atom

Location in the atom

Electric charge

Relative mass

Proton Slightly less massive than a neutron

Nucleus

1–

12 Compare How are two atoms of the same element alike?

14 Calculate Look at the model of a helium atom shown in the Student Edition. Use this model to find its atomic number and mass number.

Atomic number:

Mass number:

34 Unit 3 Introduction to Chemistry

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LessonLesson ReviewVocabularyDraw a line to connect the following terms to their definitions.

1 atom2 proton3 neutron

A a positively charged atomic particle

B an uncharged atomic particleC the smallest particle of an

element that has the chemical properties of that element

Key Concepts4 Compare Compare the charges and masses of

protons, neutrons, and electrons.

5 Explain How can atoms make up all of the substances around you?

6 Compare How does the current model of the atom differ from J. J. Thomson’s model?

7 Calculate What is the atomic number of a sodium atom that has 11 protons and 12 neutrons?

Critical ThinkingUse this diagram to answer the following questions.

8 Analyze The red sphere represents a proton. What is the atomic number of this atom? Explain how you found the atomic number.

9 Apply What is the mass number of an isotope of this atom that has 2 neutrons?

10 Analyze Where are the nucleus and the electrons located in this atom?

11 Infer If atoms are made of smaller parts such as electrons, why are atoms considered the basic unit of matter?

Lesson Review Answers1. C

2. A

3. B

4. Protons are positive, neutrons have no charge, and electrons are nega-tive. Neutrons have the greatest mass. Protons are slightly less mas-sive than neutrons. Electrons are much less massive than protons and neutrons.

5. Chemical bonds join different types of atoms and different numbers of atoms together in different combina-tions to form many substances.

6. In the current model of the atom, electrons move around the nucleus within an area called the electron cloud. In J. J. Thomson’s model, elec-trons are spread throughout the atom.

7. 11

8. The atomic number is 1. The atomic number is equal to the number of protons.

9. 3

10. The nucleus is in the center of the atom where the red circle is. The electrons are in the blue area, which is the electron cloud.

11. An atom is the smallest particle of an element that still has the properties of the element. Matter is made up of combinations of atoms.

123Lesson 1 The Atom

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3535Lesson 1 The Atom

Name: Date: Class:

Lesson The Periodic Table (p. 124)2

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1 Describe Write a word or phrase beginning with each letter of the word GOLD that describes the properties of the gold coins shown in the Student Edition.

G

O

L

D

2 Describe As you will learn in this lesson, elements are arranged by their properties on the periodic table. What other objects are often arranged by their properties?

3 Preview Before you begin reading this lesson, look through the pages and read the headings and subheadings. The headings show how information is organized in the lesson. After you read the headings and subheadings, write a short description of what the lesson will cover.

5 Identify Observe the appearance of the six elements shown in the Student Edition. Create two or three categories that group the elements by similar properties. On the lines below, write the name of the category in which the element belongs.

Sulfur:

Chlorine:

Copper:

Bromine:

Mercury:

Bismuth:

6 Explain How did Henry Moseley revise Mendeleev’s periodic table?

7 Apply What are you doing this week? Fill in the calendar on the next page with activities or plans you have for this week and next. Do any events occur periodically? Explain.

8.5B; 8.5C

36

Unit 3

Unit 3 Introduction to Chemistry


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Sunday Monday Tuesday

Wednesday Thursday

Friday Saturday

8 Analyze According to the periodic table, how many elements are a liquid at room temperature?

9 Analyze According to the periodic table, how many

elements are metalloids?

10 Apply What is the average atomic mass of aluminum?

11 Identify Look at the photos in the Student Edition. Fill in the blanks with the word metal, nonmetal, or metalloid.

Iron:

Silicon:

Carbon:

12 Explain Why do elements within a group have similar chemical properties?

14 Analyze List three other elements that have 1 valence electron. (Hint: Refer to the periodic table.)

15 Analyze List three other elements that have 8 valence electrons. (Hint: Refer to the periodic table.)

37Lesson 2 The Periodic Table

8_CFLAESE365756_182Afinal10-23-09LKell

58.69 63.55

106.42 107.87

Nickel Copper

Palladium Silver

28 29

46 47

Palladium

46

PdSilver

47

Ag

Nickel

28

NiCopper

29

Cu

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VocabularyDraw a line to connect the following terms to their definitions.1 metal2 nonmetal3 metalloid

A an element that has properties of both metals and nonmetals

B an element that is shiny and that conducts heat and electricity well

C an element that conducts heat and electricity poorly

Key Concepts4 Identify Elements in the same

on the periodic table have the same number of valence electrons.

5 Identify Properties of elements within a on the periodic table change in a predictable way from one side of the table to the other.

6 Identify The number of in an atom determines the identity of the element.

7 Describe What is the purpose of the zigzag line on the periodic table?

8 Apply Thorium (Th) has an average atomic mass of 232.04 u and an atomic number of 90. In the space below, draw a square from the periodic table to represent thorium.

Critical ThinkingUse this graphic to answer the following questions.

9 Infer What can you infer about copper and silver based on their position relative to each other?

10 Apply How does the nucleus of a copper atom compare to the nucleus of a nickel atom?

11 Explain Explain how chemists can state with certainty that no one will discover an element that would appear on the periodic table between sulfur (S) and chlorine (Cl).

Lesson Review Answers 1. B

2. C

3. A

4. group (or family)

5. period

6. protons

7. The zigzag line on the periodic table separates metals and nonmetals.

8. Students should draw a square that shows the atomic number (90), chemical symbol (Th), element name (thorium), and average atomic mass (232.04 u) of thorium. Refer to the periodic table for proper placement of each piece of information.

9. Sample answer: Atoms of copper and silver have the same number of valence electrons, so they will behave similarly in chemical reac-tions.

10. The nucleus of a copper atom contains one more proton than the nucleus of a nickel atom.

11. The elements are arranged in order of increasing atomic number. Sulfur has an atomic number of 16, and chlorine has an atomic number of 17. There is no whole number between these two numbers, so an element cannot appear between sulfur and chlorine.

135Lesson 2 The Periodic Table

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Electrons and Chemical Bonding (p. 136)

Lesson 31 Predict Check T or F to show whether you think each

statement is true or false.

T F

The nucleus of an atom does not change when the atom undergoes a chemical reaction.

An atom does not react with other atoms if it has the same number of protons as it has electrons.

All of an atom’s electrons can interact with the electrons of other atoms to form bonds.

2 Describe Fill in the blank with the word or phrase that you think correctly completes the following sentences. Use the model of a lithium atom shown in the Student Edition. Write your answers on the lines below the sentences.

The represents the location of the electrons.

The is represented by the red and silver spheres.

3 Apply Many scientific words, such as bond, also have everyday meanings. Use context clues to write your own definition for each meaning of the word bond.

Example sentence: Zach used glue to form a bond between the broken parts of the chair.

bond:

Example sentence: A chemical bond can form between two atoms.

bond:

5 Describe What are chemical bonds?

8 Apply Look at the diagram of a chemical reaction shown in the Student Edition. How many of each type of atom are there on each side of the arrow?

H: Cl:

9 Infer How can you tell that atoms are not created or destroyed by the chemical change shown in the Student Edition?

10 Describe Look at the models of hydrogen in the Student Edition. Write a caption for each model of hydrogen describing what it shows.

Hydrogen model (top):

Hydrogen model (bottom):

14 Apply How many valence electrons do nitrogen (N) and phosphorus (P) have?

N: P:

8.5B; 8.5C

39Lesson 3 Electrons and Chemical Bonding

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LessonLesson ReviewVocabularyCircle the term that best completes each of the following sentences.1 A chemical bond joins atoms / electrons

together in a molecule.2 In the Bohr model of an atom, valence electrons

are shown in the innermost / outermost energy level.

Key Concepts3 Relate Which of the following can happen

during a chemical change? A Atoms gain or lose protons and change into

new types of atoms. B Bonds break, and new bonds form. C Nuclei of atoms break apart and the

subatomic particles recombine. D All of the electrons in the atom are lost.4 Explain Atoms can gain, lose, or share

electrons during a chemical change. Why doesn’t this cause the atoms’ identities to change?

5 Identify Sulfur (S) is in Group 16 of the periodic table. How many valence electrons does an atom of sulfur have?

6 Model Find beryllium (Be) on the periodic table. In the space below, draw a Bohr model of a beryllium atom.

Critical ThinkingUse this model of a nitrogen atom to answer the following questions.

7 Analyze How many valence electrons do nitrogen atoms have?

8 Infer Explain whether nitrogen atoms will form bonds with other atoms.

9 Distinguish How would a Bohr model of a neon atom differ from this model of nitrogen?

10 Apply Imagine that you need to make a model that shows the locations of the parts of a sodium atom. Explain which type of model you would use.

Lesson Review Answers 1. atoms

2. outermost

3. B

4. The atoms do not gain or lose protons, so their identities don’t change.

5. 6

6. Students should draw a Bohr model with 2 energy levels. There should be 2 electrons in the first level and 2 in the second.

7. 5

8. Nitrogen atoms have fewer than eight valence electrons. They will form bonds with other atoms to fill the outermost energy level.

9. A neon atom would have eight electrons in the second energy level.

10. I would use an electron cloud model to show the general locations of the nucleus and electrons in a sodium atom.

145Lesson 3 Electrons and Chemical Bonding

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Chemical Reactions (p. 148)Lesson 41 Identify Unscramble the letters below to find two

types of energy that can be released when chemical reactions occur. Write your words on the blank lines.

GLITH

DSNUO

2 Describe Write your own caption to the photo shown in the Student Edition. Describe what kind of changes have happened to the ship and anchor.

3 Synthesize You can often define an unknown word if you know the meaning of its word parts. Use the word parts and sentence below to make an educated guess about the meaning of the word exothermic.

Word part Meaning

exo- go out, exit

therm- heat

Example sentence: Exothermic reactions can sometimes quickly release so much heat that they can melt iron.

exothermic:

5 Identify Look at the photos in the Student Edition. For each photo, identify the evidence that a chemical reaction has taken place. Write your answers on the lines below.

A

B

C

D

6 Identify Circle the subscript in the chemical formula below.

H2O7 Analyze Look at the chemical reaction shown in the

Student Edition. Use what you know about chemical formulas to identify the product in this reaction.

8 Apply Look at the chemical reaction shown in the Student Edition. How many atoms of each element are in one molecule of the product?

9 Compare What is the difference between a coefficient and a subscript?

8.5D; 8.5E; 8.5F

41Lesson 4 Chemical Reactions

Unit 3

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10 Calculate Fill in the blanks below to balance the chemical equation. Sketch the products and reactants to show that the number of each type of atom is the same.

Identify

A Count the atoms of each element in the reactants and product in the unbalanced equation. Look at the Student Edition to see a diagram that shows models of the molecules involved in this reaction.

H2 + O2 H2O

H = O = H = O =

Solve

B To balance the number of each type of atom, place coefficients in front of the appropriate chemical formulas. Sketch the products and reactants, showing the correct number of molecules of each.

H2 + O2 H2O

+

H = O = H = O =

12 List Name three everyday exothermic chemical reactions.

13 Describe What happens to the energy absorbed during an endothermic reaction?

14 Compare Use the Venn diagram to compare endothermic and exothermic reactions. Write words and phrases to complete each part of the Venn diagram on the lines below.

Endothermic

Both

Exothermic

Endothermic Both Exothermic


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LessonLesson ReviewVocabularyDraw a line to connect the following terms to their definitions.1 reactant2 product

A a substance that is produced by a chemical reaction

B a substance that participates in a chemical reaction

Key Concepts3 Describe What happens to the atoms in the

reactants during a chemical reaction?

4 Explain How does a balanced chemical equation show that mass is never lost or gained in a chemical reaction?

5 Relate Describe four ways you could increase the rate of a chemical reaction.

6 Compare How do exothermic and endothermic reactions differ?

Critical ThinkingUse this diagram to answer the following questions.

7 Model The reactants in the above reaction are hydrogen (H2) and nitrogen (N2). The product is ammonia (NH3). In the space below, write a balanced chemical equation that represents the reaction.

8 Analyze This reaction releases energy as heat. Explain whether the reaction is exothermic or endothermic and whether it obeys the law of conservation of energy.

9 Evaluate Two colorless solutions are mixed together. Bubbles form as the solution is stirred. Give two possible explanations for this result.

10 Apply The chemical formula of glucose is C6H12O6. What are the names of the elements in glucose, and how many atoms of each element are present in a glucose molecule?

Lesson Review Answers 1. B

2. A

3. The atoms in the reactants are rearranged to form the products.

4. A balanced chemical equation shows that the reactants have the same numbers of each type of atom as the products. It shows that atoms are not created or destroyed.

5. I could add a catalyst, increase the concentration of the reactants, increase the surface area of solid reactants, or increase the tempera-ture.

6. Exothermic reactions release energy. Endothermic reactions absorb energy.

7. N2 + 3H2 → 2NH3

8. It is exothermic; it obeys the law of conservation of energy because the total of the energy released plus the energy stored in the ammonia is equal to the energy stored in the hydrogen and oxygen.

9. Sample answer: The formation of bubbles could be evidence that a chemical reaction took place and a gas was formed. Or, the bubbles could be air bubbles that were trapped in the solution when it was stirred.

10. 6 atoms of carbon, 12 atoms of hydrogen, and 6 atoms of oxygen


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You Try It!Acid precipitation can cause a lake to become acidic and unsuitable for living things. One way to reduce the acidity is to add a base. The chemical equation below shows the reaction that takes place when the base calcium hydroxide reacts with sulfuric acid in acid precipitation. Use the skills you’ve reviewed to balance this chemical equation.

1 Identify how many atoms of each element are present in each chemical formula.

Complete the table at the right by identifying the number of each type of atom in the reactants and in the products. (Hint: You may refer to the periodic table to find the name of unfamiliar elements.)

2 Compare the number of each type of atom in the reactants to the number of each type of atom in the products.

Compare the number of atoms in the reactants to the atoms in the products. Which elements are not balanced on both sides of the equation?

Reactants ProductsCalcium = 1 Calcium = 1

3 Add coefficients to balance the chemical equation.

Add coefficients in front of the chemical formulas at the right to balance the chemical equation.

4 Check your work.

Are there equal numbers of each type of atom on both sides of the yields sign? Record the number of each type of atom in the table.

Reactants Products

Ca(OH)2 + H2SO4 → CaSO4 + H2O

The acidity of a lake can be adjusted by adding a base.

Ca(OH)2 + H2SO4 → CaSO4 + H2O

Think Science

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4444 Unit 3 Think Science

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My Notes


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4545Unit 3 Introduction to Chemistry

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InCopy Notes1. This is a list

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Unit 3 ReviewName

Unit 3 ReviewVocabularyFill in the blank with the term that best completes the sentence.

8.5C

1 Elements in the periodic table are arranged in columns, or .

2 A(n) is the smallest particle of an element that has the chemical properties of that element.

3 A(n) is a negatively charged subatomic particle.

4 A chemical is an interaction that holds two atoms together.

8.5D

5 A combination of chemical symbols and numbers to represent a substance is a chemical .

Key ConceptsChoose the letter of the best answer.

8.5B

6 The chart below gives the atomic number and mass number of two elements.

Element A Element BAtomic number 10 9Mass number 20 19

How many protons does Element B have?

A 9 C 19

B 10 D 20

8.5E

7 Which of the following is an example of an endothermic reaction? (Hint: Step 1. Recall what happens to energy in an endothermic reaction. Step 2. Identify the event that matches how energy behaves during an endothermic reaction.)

A a cake baking C a firework exploding

B a candle burning D a piece of wood smoldering

Answers

165Unit 3 Review

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8_CFLAEAG365848_24AFirst Pass 10-29-09Precision Graphics

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Unit 3 Review continued

8.5A

8 Which model of an atom is correctly labeled?

A

B

C

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Unit 3 Review

Name

8.5C

9 Magnesium has one more valence electron than lithium has. What can you infer about magnesium’s location on the periodic table? (Hint: Step 1. Recall how the number of valence electrons affects placement of an element on the periodic table. Step 2. Infer which statement is true based on how the number of valence electrons affects placement on the periodic table.)

A Magnesium is in the first group.

B Magnesium is directly below lithium.

C Magnesium and lithium are in different groups.

D Magnesium is directly to the right of lithium.

10 Which of the analogies best describes a Bohr model of an atom? (Hint: Step 1. Recall what the Bohr model looks like. Step 2. Decide which analogy best fits what the Bohr model looks like.)

A A Bohr model is like a bowling ball because they are both solid spheres.

B A Bohr model is like a model of the solar system because they both show orbits around a massive center.

C A Bohr model is like a string of beads because they both contain small parts that are lined up in a row.

D A Bohr model is like a jigsaw puzzle because they are both made up of small parts that are all joined together.

Gridded ResponseWrite your answer in the boxes, then bubble in the corresponding number in the grid below.

8.5D

11 The following chemical equation shows the reaction of methane and oxygen to form carbon dioxide and water.

CH4 + 2O2 → CO2 + H2O

What coefficient must be placed in front of water to balance the equation?

.0 0 0 0 0 0

1 1 1 1 1 1

2 2 2 2 2 2

3 3 3 3 3 3

4 4 4 4 4 4

5 5 5 5 5 5

6 6 6 6 6 6

7 7 7 7 7 7

8 8 8 8 8 8

9 9 9 9 9 9

167Unit 3 Review

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Unit 3 Review continued

Critical ThinkingAnswer the following questions in the space provided.

8.5C

12 List three properties of metals that nonmetals typically do not have.

Describe where metals and nonmetals are found on the periodic table.

What are elements that have some properties of metals and some properties of nonmetals called?

ESSENTIAL QUESTIONSLessons 1 and 3

Connect

Answer the following questions in the space provided.

8.5B

13 In the space below, draw a Bohr model of an atom.

How many valence electrons does this atom have?

What element does your atom represent? Explain.

Bohr models do not correctly show the location of electrons in an atom. Explain why they are still useful for predicting bonding of atoms.


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