5 1 building blocks of matter (physical sciences)

California Leveled Science Readers (Grade 5) Content leveled readers teach science concepts, vocabulary, and reading skills – at each student’s reading level – and allow students to read and explore the wonders of nonfiction. Leveled science readers deliver science content to help address the individual needs of all students. They reinforce reading skills and strategies while promoting science understanding. Each grade 5 science reader is a richly illustrated, selfcontained little book with 10 to 14 double pages. BELOW 5.1 Building Blocks of Matter (Physical Sciences) 5.2 Changes in Matter (Physical Sciences) 5.3 Basic Structures of Organisms (Life Sciences) 5.4 MISSING 5.5 Water on Earth (Earth Sciences) 5.6 Weather (Earth Sciences) 5.7 The Solar System (Earth Sciences) ON 5.1 Understanding Matter (Physical Sciences) 5.2 How Matter Changes (Physical Sciences) 5.3 The Building Blocks of Organisms (Life Sciences) 5.4 Systems of the Human Body (Life Sciences) 5.5 Earths Hydrosphere (Earth Sciences) 5.6 How Weather Works (Earth Sciences) 5.7 Earths Solar System (Earth Sciences) ADVANCED 5.1 Atoms (Physical Sciences) 5.2 Acids and Bases at Work (Physical Sciences) 5.3 MISSING 5.4 MISSING 5.5 MISSING 5.6 Hurricanes (Earth Sciences) 5.7 The Red Planet (Earth Sciences)

Genre Comprehension Skill Text Features Science Content

Nonfi ction Make Inferences • Captions

• Charts

• Diagrams

• Glossary

Matter

Scott Foresman Science 5.1

Standards Preview

Standard Set 5 Physical Sciences

5 Elements and their combinations

account for all the varied types of

matter in the world As a basis for

understanding this concept:

5.b. Students know all matter is made

of atoms, which may combine to form

molecules.

5.c. Students know metals have

properties in common, such as high

electrical and thermal conductivity

Some metals, such as aluminum (Al),

iron (Fe), nickel (Ni), copper (Cu),

silver (Ag), and gold (Au), are pure

elements; others, such as steel and

brass, are composed of a combination

of elemental metals.

5.d. Students know that each element is

made of one kind of atom and that the

elements are organized in the periodic

table by their chemical properties.

5.e. Students know scientists have

developed instruments that can create discrete images of atoms and molecules that show that the atoms and molecules often occur in well-ordered arrays.

5.f. Students know differences in

chemical and physical properties

of substances are used to separate mixtures and identify compounds.

5.h Students know living organisms

and most materials are composed of just a few elements.

5.i. Students know the common

properties of salts, such as sodium chloride (NaCl).

ISBN 0-328-23563-6 ì<(sk$m)=cdfgdg< +^-Ä-U-Ä-U

by Marcia K Miller

Physical Sciences

atom

atomic number

chemical property

compound

element

molecule

physical property

solution

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1 2 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06

by Marcia K Miller

What are properties

of matter?

All matter is made up of elements Elements are the

building blocks of matter They cannot be broken into

smaller pieces More than 100 basic elements combine

to make up matter Earth’s crust is mostly made up of

eight elements They are oxygen, silicon, aluminum, iron,

calcium, sodium, potassium, and magnesium Which ones

have you heard of?

Most matter is made of groups of elements Most living

and nonliving things are made of a few elements put

together in many ways Elements make up all the minerals

on Earth You will learn more about how so many different

materials come from only a few elements

Gold is an element.

Balance

Spring scale

3

Each element has its own special properties These

properties set each element apart from the rest Physical

properties can be seen or measured without changing

a material Color, odor, and mass are physical properties

Chemical properties describe how a material changes

into other materials Rust is a chemical property of iron

You can observe, describe, and measure physical properties

Some tools you might use are meter sticks, thermometers, balances, and spring scales

Physical Properties

of Matter

Looking at the picture of copper

you can see that it is shiny and solid

These are two physical properties of

copper The color, hardness, and state

of matter (such as solid or liquid) are

physical properties too

Copper also has mass and weight

It’s easy to confuse these two properties Mass

measures the amount of matter in an object A balance can

measure mass Weight measures the pull of gravity on an

object A spring scale can measure weight

Weight changes if an object moves to a place with

different gravity You have the same mass on Earth as on

the Moon Your weight on Earth is six times greater than it

would be on the Moon! Magnetism, freezing, and boiling

point are physical properties too

Water freezes at 0°C Ice melts

at 0°C The temperatures at which substances freeze and melt are physical properties.

5

Chemical Properties of Matter

A chemical property shows how a substance changes when it mixes with something else As wood burns, new materials form They are ash and gases The ability of a material to burn is called fl ammability Other materials change when they mix with acids Look at the picture of the zinc nail It bubbles when it is placed in an acid This

is a chemical property The chart lists some physical and chemical properties of substances you know

Whether a material changes when mixed with acid is a chemical property of the material The zinc nail changes and forms bubbles in the beaker

of acid The gold chain does not.

Wood Does not conduct electricity Flammable

Iron Can be hammered into sheets Combines with oxygen to

form rust Water Colorless and odorless Does not burn

Copper Conducts electricity Combines with oxygen to form the

mineral cuprite

Some Common Properties

Carbon atom

6

What makes up

matter?

Atoms and Elements

An atom is the smallest particle of an element that

still has all the same properties of the element The

atoms of each element are different The structures of

atoms determine the properties of an element They also

determine if elements can combine

An element is made of only one kind of atom Suppose

you could see the structure of aluminum You would fi nd

that it is made of many tiny atoms of the same kind This

is why elements are called pure substances They cannot be

separated into simpler substances

Atoms are made of even smaller parts The atom’s

center is called the nucleus Electrons surround the nucleus

They have a negative charge The nucleus has neutrons

and protons A neutron has no electrical charge A proton

has a positive charge The number of protons in a nucleus

gives an element its own atomic number

Carbon atoms form graphite, which is used in pencils.

N

N nitrogen molecule

7

Molecules

You read that the smallest particle of a substance is an element But many substances are made of more than single atoms of one

element Atoms can combine A molecule

is a particle that is made from more than one atom It is also the smallest part of a substance that still has all of its properties

Atoms share electrons in some molecules

These atoms bind together in the molecule

Scientists have been studying atoms and molecules for

a long time These tiny particles can’t be seen, but scientists have come up with a model for how they look They use technology to make images of atoms and molecules

This is how graphite looks when seen through a scanning tunneling microscope (STM).

Periodic Table of Elements

8

Elements and the Periodic Table

The elements we know about are in a table called the

periodic table of elements They are organized by their

atomic number The atomic numbers increase across the

table from left to right They also increase as you go down

a column Elements in the same column have similar

chemical properties You can predict the properties of an

element if you know its column

Every element has its own symbol The symbol has one

or two letters Only the fi rst letter is capitalized Look at the

periodic table to see how information is organized

metals metalloids (semimetals) nonmetals

9

Classifying Elements

Each element is made of one kind of atom This atom has a unique number of protons and electrons These protons and electrons give each element its properties Scientists use these properties

to sort elements into three groups These groups are metals, nonmetals, and metalloids

Metals are usually solid They conduct heat and electricity well Metals can be pulled into wires and

fl attened into sheets Nonmetals are usually brittle This means that they can crack or break easily Nonmetals

do not conduct heat and electricity well They cannot be

fl attened into sheets or made into wires Metalloids have some properties of metals and nonmetals

atomic number

chemical symbol

Period 4

10

Information on the Periodic Table

The periodic table is made of small blocks Look at the

block for chromium It shows what kind of information you

can fi nd out about each element on the periodic table

The word periodic means “in a regular, repeated

pattern.” An element’s location on the periodic table tells

you about it The properties of elements change as you

move across a row or down a column

The periodic table has 18 columns Each column

is called a group or family The elements in a group

have things in common They react—or cause chemical

changes—with other substances in similar ways

Titanium, like these bars,

is a strong but light metal.

Group 18

11

Except for hydrogen, all of the elements in Group 1 are metals They all react strongly with water Potassium is

in Group 1 Atoms of hydrogen have structures similar to elements in Group 1 But hydrogen has different properties

Each row in the periodic table is called a period The elements in a period have very different properties Look at Period 4 below The metallic elements change as you move from left to right Elements at the left are very active They get less active as you move right The elements in blue are metalloids The last three elements are nonmetals

Metals and their Properties

Metals have many properties in common Most metals

are shiny Metals are malleable This means that they can

be bent and shaped without breaking All metals (except

mercury) are solids at room temperature

Most metals conduct heat and electricity well

Conductors let heat and electricity pass through them

easily Most metals can also be made into wire These

properties make some metals useful in electrical devices

Copper and silver are pure metallic elements Each

is made up of only one kind of atom Many other

metals are also pure elements

Copper wire conducts electricity.

Nickel is used in

some batteries.

13

Metal Mixtures

Mixing different elements together makes metals that are not pure elements An alloy

is a mixture of two or more metal elements

Alloys have properties that are more useful than the metals that form them

Metal alloys have many uses Steel is an alloy made from iron and carbon Steel is stronger than iron Steel is used in making everything from bridges to safety pins Brass

is another common metal alloy It is an alloy

of copper and zinc Brass is sturdier than copper It looks better than zinc

This saxophone is made of brass

These safety pins are made of steel

water molecule

C

carbon dioxide molecule

14

What are

compounds?

Properties of Compounds

A compound is a kind of matter made when two

or more elements combine Compounds have properties

different from the elements that make them Sugar is made

of atoms of carbon, hydrogen, and oxygen Pure oxygen

and hydrogen are invisible gases at room temperature

They have no taste Black coal is made mostly of pure

carbon atoms Coal does not taste sweet! But a sweet, white

solid forms when those same three elements combine in just

the right way

Every compound has its own formula The formula

shows how many atoms of each element are in the

compound Water is a compound Its formula is H20 The

small “2” after the “H” shows that a molecule of water

has two hydrogen atoms Water always has twice as many

hydrogen atoms as oxygen atoms

chlorine sodium

sodium chloride (table salt)

Sodium hydroxide and hydrogen

microscopic image

of sodium chloride

The Same Element in Different Compounds

The same element can be in more than one compound

Look at the pictures below Which element appears in both compounds? Notice that both compounds have sodium Yet they are very different

Compounds are important to your body Water is a compound Water makes up about 60 percent of your body

Other compounds make up much of your skin and bones

Each element reacts differently when it combines with different substances When sodium combines with chlorine, it forms sodium chloride You know it as common table salt.

When sodium combines with water, a violent reaction takes place The result is hydrogen gas and sodium hydroxide.

15

Salts

Salts are compounds Salts are made of particles that

are held together by opposite charges The particles can

be charged atoms or groups of atoms Particles with more

electrons than protons have a negative charge Particles

with more protons than electrons have a positive charge

There are many kinds of salts The salt you add to your

food is just one kind All salts have the same two properties

All salts are made of at least one metal element and one

nonmetal element All salts can form crystals Crystals form

when particles are arranged in a regular pattern These

crystals are brittle

Table salt is made from a

metal and a nonmetal.

17

Forming Salts

Salts can form when chemicals called acids and bases react Hydrochloric acid (HCl) and sodium hydroxide (NaOH) are two dangerous chemicals HCl is a base NaOH

is an acid They combine to form sodium chloride (NaCl) and water (H2O) Sodium chloride is common table salt It is dissolved in the water If the water evaporates, the salt is left behind in crystals

Many acids and bases are dangerous

Always handle chemicals with the greatest care NEVER taste any materials formed in

a science experiment Always look for warning labels, and read them carefully

These warnings are put

on products that contain dangerous chemicals.

Poisonous

Dangerous to the Environment

Corrosive

Harmful or Irritating

Properties of Salts

What do you think of when you

hear the word salt? What properties

do salts have? You probably think

of the solid white crystals you fi nd

in a salt shaker These crystals are

sodium chloride (NaCl), or table salt

Table salt is just one of the many

salts that share common properties

You have read that salts are made

from metal and nonmetal elements

They form brittle crystals Most salts also

melt only at high temperatures

One important property of most salts

is that they dissolve in water You can try

this for yourself If you do, you will

notice something There is a point at

which no more salt will dissolve, no

matter how much you stir the water

When salts are dissolved in water they

conduct electricity well

If there is too much salt in the water, it will not dissolve.

19

The properties of salts are not like the properties of the elements that formed them Copper, oxygen, and sulfur combine to make a blue salt If copper is combined with chlorine, it makes a green salt Both of these salts are poisonous Unlike the copper that helped form them, they cannot be pulled into wire

When copper is used to make

a salt, its properties change.

Copper, sulfur, and oxygen combine to make a blue salt.

Copper and chlorine combine

to make a green salt.