The Periodic Table and Physical Properties /…iÊ Ê`i> Elements on the periodic table are grouped together based on their properties.

1 3.f, 7.a Organization of the >ˆ˜ Table ˆ} Periodic *ˆVÌÕÀi `i> >ˆ˜Ê`i> The periLESSON

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2 7.a, 7.b, 9.e ˆ} >ˆ˜ Isotopes and *ˆVÌÕÀi `i> LESSON

Radioactivity

,i>`ˆ˜} >ˆ˜Ê`i>

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radioactive isotopes decay at varying rates.

3 5.d, 7.c, 9.a Physical Properties and Changes ˆ} >ˆ˜ LESSON

*ˆVÌÕÀi `i> >ˆ˜Ê`i> Substances

have physical properties ,i>`ˆ˜} that can be described

…iVŽ and physical changes that can be observed. >ˆ˜ Taking It ˆ}for Granite *ˆVÌÕÀi `i>

Barre quarry in Vermont is America’s oldest granite quarry. This quarry contains granite, which is composed of feldspar, ,i>`ˆ˜}

…iVŽand mica. These minerals are composed of elements, such as silicon, quartz, oxygen, calcium, and potassium.

-Vˆi˜ViÊÊ+PVSOBM Write a paragraph explaining why you think it’s helpful to keep your books, notebooks, and papers organized. 286 Joseph Sohm/CORBIS

Start-Up Activities

Which element are you? How can you organize your class into a periodic table?

Regions of the Periodic Table Make the following Foldable to identify the regions of the periodic table. STEP 1 Fold a sheet of paper into thirds lengthwise.

Procedure 1. Find your assigned element on the periodic table. Color the poster board the same color as your element’s block. 2. Use a dark marker to print your element’s atomic number, symbol, name, and atomic mass on your poster board.

STEP 2 Unfold and draw lines along the folds. Draw three vertical lines to divide the paper into four columns, as shown.

3. Find the classmates whose elements are to the left, to the right, above, and below your element on the periodic table. 4. Arrange yourselves so that you are in the correct positions.

Think About This • Explain why you and your classmates arranged yourselves as you did. • Assess What limitations did you find in making the table? 3.f

Clarifying Label the top row of your Foldable with the names of the regions. In the boxes below, describe the location, the properties, and some examples of elements in that region.

Visit ca8.msscience.com to: ▶ ▶ ▶ ▶

view explore Virtual Labs access content-related Web links take the Standards Check

287 Horizons Companies

Get Ready to Read Make Predictions Learn It!

A prediction is an educated guess based on what you already know. One way to predict while reading is to guess what you believe the author will tell you next. As you are reading, each new topic should make sense because it is related to the previous paragraph or passage.

Practice It!

Read the excerpt below from Lesson 3. Based on what you have read, make predictions about what you will read in the rest of the lesson. After you read Lesson 3, go back to your predictions to see if they were correct. Predict whether a solution could be formed from salt and water.

What would you predict would be a characteristic of all solutions?

Dissolving is mixing a substance into another substance to form a solution. As sugar dissolves in water, it disappears and seems to become part of the water. But if you boil the water away, the sugar becomes visible again. Dissolving is a physical change because the sugar is unchanged. —from page 317

Can you predict another kind of change that matter could undergo?

Apply It!

Before you read, skim the questions in the Standards Review. Choose three questions and predict the answers. 288

Target Your Reading

heck the see c , d a e r e to As you you mad s n o i t c i t. pred e correc r e w y e h if t

Use this to focus on the main ideas as you read the chapter. 1

Before you read the chapter, respond to the statements below on your worksheet or on a numbered sheet of paper. • Write an A if you agree with the statement. • Write a D if you disagree with the statement.

2

After you read the chapter, look back to this page to see if you’ve changed your mind about any of the statements. • If any of your answers changed, explain why. • Change any false statements into true statements. • Use your revised statements as a study guide.

Before You Read A or D

Statement

After You Read A or D

1 The elements are arranged on the periodic table according to their atomic numbers and mass numbers. 2 The elements in a group have similar properties. 3 Metals are located on the right side of the periodic table. 4 Not all isotopes are radioactive. 5 Radioactive elements have unstable nuclei. 6 An element’s mass number is the number of neutrons in its nucleus. Print a worksheet of this page at ca8.msscience.com.

7 Transmutation is another word for half-life. 8 Melting and boiling points change with pressure. 9 Thermal conductivity occurs because particles collide with one another. 10 Density is a physical property that depends on the size of a sample. 289

LESSON 1 Science Content Standards 3.f Students know how to use the periodic table to identify elements in simple compounds. 7.a Students know how to identify regions corresponding to metals, nonmetals, and inert gases.

Reading Guide What You’ll Learn ▼

Describe the arrangement of the elements in the periodic table.

▼

Identify metals, nonmetals, and semimetals by their positions in the periodic table.

▼

Identify and describe the noble gases.

Why It’s Important The periodic table will provide you with a lot of information once you know how to use it.

Organization of the Periodic Table >ˆ˜Ê`i> The periodic table contains information about the structures and characteristics of elements.

Real-World Reading Connection A map is a source of much information. You can find streets, cities, lakes, and rivers on a map. But you must first know how to read the map. The periodic table is similar to a map. You can learn a lot about the elements once ˆ} you learn how to read the periodic table. >ˆ˜ `i>

*ˆVÌÕÀi

How are the elements arranged? ,i>`ˆ˜}

…iVŽ what a library would be like if books weren’t orgaImagine nized on the shelves. You wouldn’t be able to find the information you needed. Like a library, the periodic table is a system for organizing information. Recall that each element has a different atomic number. The atomic number is the number of protons in an atom of an element. The elements are arranged in the periodic table according to their atomic numbers. Each element block contains the same type of information. The block for carbon is shown in Figure 1. A key at the top of the table shows that each block contains the element’s name, atomic number, symbol, and atomic mass. Each block also has an icon, or a picture. The icon indicates whether the element is normally a gas, a liquid, or a solid. Another icon shows whether the element is found in nature or is made by humans.

Vocabulary period group metallic luster conductivity halogen noble gas

Review Vocabulary

What do the icons in the element blocks show?

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