© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

163

8_CTXESE025547_U03A.indd 1 3 11/21/12 10:20 PM

InCopy Notes1. This is a list

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

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

8_CTXESE025547_U03A.indd 165 10/1/2013 12:58:18 AM

Name: Date: Class: ©

Hou

ghto

n M

ifflin

Har

cour

t Pub

lishi

ng C

ompa

ny

4747Unit 3 Introduction to Chemistry

++

+ Electrons

Proton

Nucleus

Neutron ++

+ Proton

Nucleus

Electrons

Neutron

++

+ Proton

Neutron

Electrons

Neutron

Proton

Electrons

Nucleus ++

+Nucleus

C

B

D

A

8_CFLAEAG365848_24AFirst Pass 10-29-09Precision Graphics

++

+ Electrons

Proton

Nucleus

Neutron ++

+ Proton

Nucleus

Electrons

Neutron

++

+ Proton

Neutron

Electrons

Neutron

Proton

Electrons

Nucleus ++

+Nucleus

C

B

D

A

8_CFLAEAG365848_24AFirst Pass 10-29-09Precision Graphics

++

+ Electrons

Proton

Nucleus

Neutron ++

+ Proton

Nucleus

Electrons

Neutron

++

+ Proton

Neutron

Electrons

Neutron

Proton

Electrons

Nucleus ++

+Nucleus

C

B

D

A

8_CFLAEAG365848_24AFirst Pass 10-29-09Precision Graphics

++

+ Electrons

Proton

Nucleus

Neutron ++

+ Proton

Nucleus

Electrons

Neutron

++

+ Proton

Neutron

Electrons

Neutron

Proton

Electrons

Nucleus ++

+Nucleus

C

B

D

A

8_CFLAEAG365848_24AFirst Pass 10-29-09Precision Graphics

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

Unit 3 Review continued

8.5A

8 Which model of an atom is correctly labeled?

A

B

C

D

166 Unit 3 Introduction to Chemistry

8_CTXESE025547_U03A.indd 1 11/21/12 10:17 PM

Name: Date: Class:

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

4848 Unit 3 Introduction to Chemistry

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

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

8_CTXESE025547_U03A.indd 1 7 11/21/12 10:17 PM

Name: Date: Class: ©

Hou

ghto

n M

ifflin

Har

cour

t Pub

lishi

ng C

ompa

ny

4949Unit 3 Introduction to Chemistry

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

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.

168 Unit 3 Introduction to Chemistry

8_CTXESE025547_U03A.indd 1 8 11/21/12 10:17 PM

Name: Date: Class:

© H

ough

ton

Miff

lin H

arco

urt P

ublis

hing

Com

pany

5050 Unit 3 Introduction to Chemistry