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2. Standardized Test Prep
Resources
Chapter Presentation
Visual Concepts
Transparencies
Standardized Test Prep
Brain Food Video Quiz

3. Chapter 4 Table of Contents Section 1 Matter
Earth Chemistry
Table of Contents
Section 1 Matter
Section 2 Combinations of Atoms

4. Chapter 4
Section 1 Matter
Objectives
Compare chemical properties and physical properties of matter.
Describe the basic structure of an atom.
Compare atomic umber, mass number, and atomic mass.
Define isotope.
Describe the arrangement of elements in the periodic table.

5. Chapter 4 Properties of Matter
Section 1 Matter
Properties of Matter
matter anything that has mass and takes up space
Every object in the universe is made up of particles of matter. The amount of matter in any object is the mass of that object.
All matter has two types of distinguishing properties—physical properties and chemical properties.

6. Properties of Matter, continued
Chapter 4
Section 1 Matter
Properties of Matter, continued
Physical properties are characteristics that can be observed without changing the composition of the substance.
Physical properties include density, color, hardness, freezing point, boiling point, and the ability to conduct an electric current.
Chemical properties are characteristics that describe how a substance reacts with other substance to produce different substances.

7. Comparing Physical and Chemical Properties
Chapter 4
Section 1 Matter
Comparing Physical and Chemical Properties

8. Properties of Matter, continued
Chapter 4
Section 1 Matter
Properties of Matter, continued
Elements
element a substance that cannot be separated or broken down into simpler substances by chemical means; all atoms of an element have the same atomic number
Each element has a characteristic set of physical and chemical properties that identify it.
Every known element is represented by a symbol of one or two letters.

9. Properties of Matter, continued
Chapter 4
Section 1 Matter
Properties of Matter, continued
Atoms
Elements are made of atoms.
atom the smallest unit of an element that maintains the chemical properties of that element
A single atom is so small that its size is difficult to imagine.

10. Chapter 4 Atomic Structure Section 1 Matter
Even though atoms are very tiny, they are made up of smaller parts called subatomic particles.
There are three types of subatomic particles—protons, electrons, and neutrons.
proton a subatomic particle that has a positive charge and that is located in the nucleus of an atom; the number of protons of the nucleus is the atomic number, which determines the identity of an element
electron a subatomic particle that has a negative charge
neutron a subatomic particle that has no charge and that is located in the nucleus of an atom

11. Atomic Structure, continued
Chapter 4
Section 1 Matter
Atomic Structure, continued
The Nucleus
The protons and neutrons of an atom form the nucleus.
The positively charged nucleus makes up most of an atom’s mass but very little of its volume. The volume of an atom is mostly empty space.
The Electron Cloud
The electrons of an atom move in a certain region of space called an electron cloud that surrounds the nucleus.
The negatively charged electrons are attracted to the positively charged nucleus. This attraction holds electrons in the atom.

12. Chapter 4
Section 1 Matter
Parts of the Atom

13. Chapter 4 Atomic Number Section 1 Matter
The number of protons in the nucleus of an atom is called the atomic number.
All atoms of any given element have the same atomic number. An element’s atomic number sets the atoms of that element apart from the atoms of all other elements.
Elements on the periodic table are ordered according to their atomic numbers.
Elements in the same column on the periodic table have similar arrangements of electrons in their atoms, and therefore have similar chemical properties.

14. Atomic Number, continued
Chapter 4
Section 1 Matter
Atomic Number, continued
The diagram below shows the atomic numbers and mass numbers of three elements.

15. Atomic Number, continued
Chapter 4
Section 1 Matter
Atomic Number, continued
The diagram below shows the periodic table.

16. Periodic Table Overview
Chapter 4
Section 1 Matter
Periodic Table Overview

17. Chapter 4 Atomic Mass Section 1 Matter
The sum of the number of protons and neutrons in an atom is the mass number.
The mass of a subatomic particle is too small to be expressed easily in grams, so a special unit called the atomic mass unit (amu) is used.
Protons and neutrons each have an atomic mass close to 1 amu.
Electrons have much less mass than protons or neutrons do. The mass of 1 proton is equal to the combined mass of about 1,840 electrons.
Because electrons add little to an atom’s total mass, their mass can be ignored when calculating an atom’s approximate mass.

18. Chapter 4 Atomic Mass, continued Reading Check
Section 1 Matter
Atomic Mass, continued
Reading Check
What is the difference between atomic number, mass number, and atomic mass unit?

19. Chapter 4 Atomic Mass, continued Reading Check
Section 1 Matter
Atomic Mass, continued
Reading Check
What is the difference between atomic number, mass number, and atomic mass unit?
The atomic number is the number of protons in an atom’s nucleus. The mass number is the sum of the number of protons and the number of neutrons in an atom. The atomic mass unit is used to express the mass of subatomic particles or atoms.

20. Chapter 4 Atomic Mass, continued Isotopes Section 1 Matter
Although all atoms of a given element contain the same number of protons, the number of neutrons may differ.
isotope an atom that has the same number of protons (or the same atomic number) as the other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass)
Because of their different number of neutrons and their different masses, different isotopes of the same element have slightly different properties.

21. Chapter 4 Atomic Mass, continued Average Atomic Mass
Section 1 Matter
Atomic Mass, continued
Average Atomic Mass
Because isotopes of an element have different masses, the periodic table uses an average atomic mass of each element.
The average atomic mass is the weighted average of the atomic masses of the naturally occurring isotopes of an element.

22. Valence Electrons and Periodic Properties
Chapter 4
Section 1 Matter
Valence Electrons and Periodic Properties
Based on similarities in their chemical properties, elements on the periodic table are arranged in columns, which are called groups.
An atom’s chemical properties are largely determined by the number of the outermost electrons in an atom’s electron cloud. These electrons are called valence electrons.
The elements that form each group commonly have the same number of valence electrons.

23. Valence Electrons and Periodic Properties, continued
Chapter 4
Section 1 Matter
Valence Electrons and Periodic Properties, continued
When an atom has 8 valence electrons, it is considered stable, or chemically unreactive. Unreactive atoms do not easily lose or gain electrons.
Elements whose atoms have only one, two, or three valence electrons tend to lose electrons easily. These elements have metallic properties and are generally classified as metals.
Elements whose atoms have from four to seven valence electrons are more likely to gain electrons. Many of these elements are classified as nonmetals.

24. Chapter 4 Objectives Define compound and molecule.
Section 2 Combinations of Atoms
Chapter 4
Objectives
Define compound and molecule.
Interpret chemical formulas.
Describe two ways that electrons form chemical bonds between atoms.
Explain the differences between compounds and mixtures.

25. Chapter 4 Molecules Section 2 Combinations of Atoms
Elements rarely occur in pure form in Earth’s crust. They generally occur in combination with other elements.
compound a substance made up of atoms of two or more different elements joined by chemical bonds
The properties of a compound differ from the properties of the elements that make up the compound.
molecule a group of atoms that are held together by chemical forces; a molecule is the smallest unit of matter that can exist by itself and retain all of a substance’s chemical properties

26. Section 2 Combinations of Atoms
Chapter 4
Compounds

27. H2O = 2 H (hydrogen atoms) + 1 O (oxygen atom)
Section 2 Combinations of Atoms
Chapter 4
Chemical Formulas
A chemical formula is a combination of letters and numbers that shows which elements make up a compound and the number of atoms of each element that are required to make a molecule of a compound.
In a chemical formula, the subscript that appears after the symbol for an element shows the number of atoms of that element that are in a molecule. For example:
H2O = 2 H (hydrogen atoms) + 1 O (oxygen atom)

28. Chapter 4 Chemical Equations Equation Structure
Section 2 Combinations of Atoms
Chapter 4
Chemical Equations
Elements and compounds often combine through chemical reactions to form new compounds.
The reaction of these elements and compounds can be described in a formula called a chemical equation.
Equation Structure
In a chemical equation, the reactants (to the left of the arrow) form the products (to the right of the arrow) through chemical reactions.
The arrow means “gives” or “yields.”

29. Chemical Equations, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Equations, continued
Equation Structure, continued
In the following equation, one molecule of methane, CH4, reacts with two molecules of oxygen, O2, to yield one molecule of carbon dioxide, CO2, and two molecules of water, H2O.
CH O  CO H2O
methane oxygen yields carbon water
dioxide

30. Chemical Equations, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Equations, continued
The diagram below shows a chemical equation.

31. Chemical Equations, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Equations, continued
Balanced Equations
A chemical equation must be balanced to be useful for showing the types and amounts of the products that could from from a particular set of reactants
An equation is balanced when the number of atoms of each element on the right side of the equation is equal to the number of atoms of the same element on the left side.
To balance an equation, you must put numbers called coefficients in front of chemical formulas.
A coefficient multiplies the subscripts in an equation.

32. Balancing a Chemical Equation by Inspection
Section 2 Combinations of Atoms
Chapter 4
Balancing a Chemical Equation by Inspection

33. Chapter 4 Chemical Bonds Section 2 Combinations of Atoms
The forces that hold together the atoms in molecules are called chemical bonds.
Chemical bonds form because of the attraction between positive and negative charges.
Atoms form chemical bonds by either sharing or transferring electrons from one atom to another.
Scientists can study interactions of atoms to predict which kinds of atoms will form chemical bonds together.

34. Chemical Bonds, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Bonds, continued
Reading Check
In what two ways do atoms form chemical bonds?

35. Chemical Bonds, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Bonds, continued
Reading Check
In what two ways do atoms form chemical bonds?
Atoms form chemical bonds by transferring electrons or by sharing electrons.

36. Chemical Bonds, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Bonds, continued
Ions
When an electron is transferred from one atom to another, both atoms become charged.
ion an atom or molecule that has gained or lost one or more electrons and has a negative or positive charge
Ionic Bonds
ionic bond the attractive force between oppositely charged ions, which form when electrons are transferred from one atom or molecule to another
A compound that forms through the transfer of electrons is called an ionic compound.

37. Chemical Bonds, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Bonds, continued
Covalent Bonds
covalent bond a bond formed when atoms share one or more pairs of electrons
A compound that forms through the sharing of electrons is called a covalent compound.
Polar Covalent Bonds
A covalent bonds in which the bonded atoms have an unequal attraction for the shared electrons is called a polar covalent compound.

38. Chemical Bonds, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Bonds, continued
The diagram below compares ionic bonds and covalent bonds.

39. Chemical Bonds, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Bonds, continued
Reading Check
Why do water molecules form from polar covalent bonds?

40. Chemical Bonds, continued
Section 2 Combinations of Atoms
Chapter 4
Chemical Bonds, continued
Reading Check
Why do water molecules form from polar covalent bonds?
The oxygen atom has a larger and more positively charged nucleus than the hydrogen atoms do. As a result, the oxygen nucleus pulls the electrons from the hydrogen atoms closer to it than the hydrogen nuclei pull the shared electrons from the oxygen. This unequal attraction forms a polar-covalent bond.

41. Chapter 4 Mixtures Heterogeneous Mixtures
Section 2 Combinations of Atoms
Chapter 4
Mixtures
mixture a combination of two or more substances that are not chemically combined
Because the substances that make up a mixture keep their individual properties, a mixture can be separated into its parts by physical means.
Heterogeneous Mixtures
Mixtures in which two or more substances are not uniformly distributed are called heterogeneous mixtures.

42. Chapter 4 Mixtures, continued Homogeneous Mixtures
Section 2 Combinations of Atoms
Chapter 4
Mixtures, continued
Homogeneous Mixtures
In chemistry, the word homogeneous means “having the same composition and properties throughout.”
solution a homogeneous mixture of two or more substances that are uniformly dispersed throughout the mixture
Liquids, gases, and solids can all be solutions.
An alloy is a solution composed of two or more metals, such as steel.

43. Chapter 4 Maps in Action Element Resources in the United States

44. Chapter 4
Earth Chemistry
Brain Food Video Quiz

45. Chapter 4 Multiple Choice Soil is an example of A. a solution
Standardized Test Prep
Multiple Choice
Soil is an example of
A. a solution
B. a compound
C. a mixture
D. an element

46. Multiple Choice, continued
Chapter 4
Standardized Test Prep
Multiple Choice, continued
Soil is an example of
A. a solution
B. a compound
C. a mixture
D. an element

47. Multiple Choice, continued
Chapter 4
Standardized Test Prep
Multiple Choice, continued
2. Isotopes are atoms of the same element that have different mass numbers. This difference is caused by
F. a different number of electrons in the atoms
G. a different number of protons in the atoms
H. a different number of neutrons in the atoms
I. a different number of nuclei in the atoms

48. Multiple Choice, continued
Chapter 4
Standardized Test Prep
Multiple Choice, continued
2. Isotopes are atoms of the same element that have different mass numbers. This difference is caused by
F. a different number of electrons in the atoms
G. a different number of protons in the atoms
H. a different number of neutrons in the atoms
I. a different number of nuclei in the atoms

49. Multiple Choice, continued
Chapter 4
Standardized Test Prep
Multiple Choice, continued
3. Which of the following statements best describes the charges of subatomic particles?
A. Electrons have a negative charge, protons have a positive charge, and neutrons have no charge.
B. Electrons have a positive charge, protons have a negative charge, and neutrons have a positive charge.
C. Electrons have no charge, protons have a positive charge, and neutrons have a negative charge.
D. In neutral atoms, protons, neutrons, and electrons have no charges.

50. Multiple Choice, continued
Chapter 4
Standardized Test Prep
Multiple Choice, continued
3. Which of the following statements best describes the charges of subatomic particles?
A. Electrons have a negative charge, protons have a positive charge, and neutrons have no charge.
B. Electrons have a positive charge, protons have a negative charge, and neutrons have a positive charge.
C. Electrons have no charge, protons have a positive charge, and neutrons have a negative charge.
D. In neutral atoms, protons, neutrons, and electrons have no charges.

51. Multiple Choice, continued
Chapter 4
Standardized Test Prep
Multiple Choice, continued
4. An element is located on the periodic table according to
F. when the element was discovered.
G. the letters of the element’s chemical symbol.
H. the element’s chemical name.
I. the element’s physical and chemical properties.

52. Multiple Choice, continued
Chapter 4
Standardized Test Prep
Multiple Choice, continued
4. An element is located on the periodic table according to
F. when the element was discovered.
G. the letters of the element’s chemical symbol.
H. the element’s chemical name.
I. the element’s physical and chemical properties.

53. Chapter 4 Short Response
Standardized Test Prep
Short Response
5. What is the name for an atom that has gained or lost one or more electrons and has acquired a charge?

54. Short Response, continued
Chapter 4
Standardized Test Prep
Short Response, continued
5. What is the name for an atom that has gained or lost one or more electrons and has acquired a charge?
an ion

55. Short Response, continued
Chapter 4
Standardized Test Prep
Short Response, continued
6. Scientists use atomic numbers to help identify the atoms of different elements. How is the atomic number of an element determined?

56. Short Response, continued
Chapter 4
Standardized Test Prep
Short Response, continued
6. Scientists use atomic numbers to help identify the atoms of different elements. How is the atomic number of an element determined?
by the number of protons in the atom

57. Chapter 4 Reading Skills Standardized Test Prep Chemical Formulas
Read the passage below. Then, answer questions 7–9.
Chemical Formulas
All substances can be formed by a combination of elements from a list of about 100 possible elements. Each element has a chemical symbol. A chemical formula is shorthand notation that uses chemical symbols and numbers to represent a substance. A chemical formula shows the amount of each kind of atom present in a specific molecule of a substance.
The chemical formula for water is H2O. This formula tells you that one water molecule is composed of two atoms of hydrogen and one atom of oxygen. The 2 in the formula is a subscript. A subscript is a number written below and to the right of a chemical symbol in a formula. When a symbol, such as the O for oxygen in water’s formula, has no subscript, only one atom of that element is present.

58. Reading Skills, continued
Chapter 4
Standardized Test Prep
Reading Skills, continued
7. What does a subscript in a chemical formula represent?
A. Subscripts represent the number of atoms of the chemical symbol they directly follow present in the molecule.
B. Subscripts represent the number of atoms of the chemical symbol they directly precede present in the molecule.
C. Subscripts represent the number of protons present in each atom’s nucleus.
D. Subscripts represent the total number of atoms present in the molecule.

59. Reading Skills, continued
Chapter 4
Standardized Test Prep
Reading Skills, continued
7. What does a subscript in a chemical formula represent?
A. Subscripts represent the number of atoms of the chemical symbol they directly follow present in the molecule.
B. Subscripts represent the number of atoms of the chemical symbol they directly precede present in the molecule.
C. Subscripts represent the number of protons present in each atom’s nucleus.
D. Subscripts represent the total number of atoms present in the molecule.

60. Reading Skills, continued
Chapter 4
Standardized Test Prep
Reading Skills, continued
8. Which of the following statements can be inferred from the information in the passage?
F. Two atoms of hydrogen are always present in chemical formulas.
G. A chemical formula indicates the elements that a molecule is made of.
H. Chemical formulas can be used only to show simple molecules.
I. No more than one atom of oxygen can be present in a chemical formula.

61. Reading Skills, continued
Chapter 4
Standardized Test Prep
Reading Skills, continued
8. Which of the following statements can be inferred from the information in the passage?
F. Two atoms of hydrogen are always present in chemical formulas.
G. A chemical formula indicates the elements that a molecule is made of.
H. Chemical formulas can be used only to show simple molecules.
I. No more than one atom of oxygen can be present in a chemical formula.

62. Reading Skills, continued
Chapter 4
Standardized Test Prep
Reading Skills, continued
9. How many atoms would be found in a single molecule that has the chemical formula S2F10?

63. Reading Skills, continued
Chapter 4
Standardized Test Prep
Reading Skills, continued
9. How many atoms would be found in a single molecule that has the chemical formula S2F10?
12 (2 of sulfur and 10 of fluorine)

64. Interpreting Graphics
Chapter 4
Standardized Test Prep
Interpreting Graphics
Use the figure below to answer questions 10–13. The figure shows the upper right segment of the periodic table.

65. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
10. Which pair of elements would most likely have a similar arrangement of outer electrons and have similar chemical behaviors?
A. boron and aluminum
B. helium and fluoride
C. carbon and nitrogen
D. chlorine and oxygen

66. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
10. Which pair of elements would most likely have a similar arrangement of outer electrons and have similar chemical behaviors?
A. boron and aluminum
B. helium and fluoride
C. carbon and nitrogen
D. chlorine and oxygen

67. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
11. What is the atomic mass of helium? F G H I

68. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
11. What is the atomic mass of helium? F G H I

69. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
12. How many neutrons does the average helium atom contain?

70. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
12. How many neutrons does the average helium atom contain? 2

71. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
Use the figure below to answer questions 13–14. The figure shows matter in three different states.

72. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
13. In what physical state is the matter in jar A?
A. solid
B. liquid
C. gas
D. plasma

73. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
13. In what physical state is the matter in jar A?
A. solid
B. liquid
C. gas
D. plasma

74. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
14. Explain how the positions and motions of particles determine the characteristics of each state of matter.

75. Interpreting Graphics, continued
Chapter 4
Standardized Test Prep
Interpreting Graphics, continued
14. Explain how the positions and motions of particles determine the characteristics of each state of matter.
Answers should include the following: jar A has a compact but unordered structure that fills the space in the bottom of the jar—this is a liquid; jar B has an ordered and self-contained structure in which the atoms are held in close, fixed positions—this is a solid; jar C shows fast-moving atoms that have no structure, that fill the entire jar, and that have no ordered relationship to each other—this is a gas.

76. Atomic Number and Atomic Mass
Chapter 4
Atomic Number and Atomic Mass

77. Chapter 4
Periodic Table

78. Chapter 4
Balancing Equations

79. Ionic Bonds and Covalent Bonds
Chapter 4
Ionic Bonds and Covalent Bonds

80. Element Resources in the United States
Chapter 4
Element Resources in the United States