1. Table of Contents Chapter Preview 4.1 Introduction to Atoms
4.2 Organizing the Elements
4.3 Metals
4.4 Nonmetals, Inert Gases, and Semimetals
4.5 Radioactive Elements
Chapter Preview
4.1 Introduction to Atoms
4.2 Organizing the Elements
4.3 Metals
4.4 Nonmetals, Inert Gases, and Semimetals
4.5 Radioactive Elements

2. Chapter Preview Questions
1. Groups of two or more atoms held together by chemical bonds are
a. elements.
b. molecules.
c. particles.
d. electrons.

3. Chapter Preview Questions
1. Groups of two or more atoms held together by chemical bonds are
a. elements.
b. molecules.
c. particles.
d. electrons.

4. Chapter Preview Questions
2. When elements are chemically combined in a set ratio, they form
a. molecules.
b. matter.
c. elements.
d. compounds.

5. Chapter Preview Questions
2. When elements are chemically combined in a set ratio, they form
a. molecules.
b. matter.
c. elements.
d. compounds.

6. Chapter Preview Questions
3. Which of the following is an example of an element?
a. copper
b. rust
c. concrete
d. water

7. Chapter Preview Questions
3. Which of the following is an example of an element?
a. copper
b. rust
c. concrete
d. water

8. Chapter Preview Questions
4. Two compounds with different properties are
a. C and O.
b. H and O.
c. CO and CO2.
d. Cl and Ar.

9. Chapter Preview Questions
4. Two compounds with different properties are
a. C and O.
b. H and O.
c. CO and CO2.
d. Cl and Ar.

10. How is the periodic table organized?
Imagine you have a piece of
aluminum foil, and you cut it
in half. If each of these pieces is
cut in half a second, third, and
fourth time, the pieces become
smaller but are still aluminum.
How small must a piece be so
that at the next cut it will no
longer be aluminum?

11. Greek Word Origins alpha First letter of the Greek alphabet
Greek Origin
Meaning
Key Words
First letter of the Greek alphabet
alpha
Alpha particle

12. Greek Word Origins atomos Cannot be cut; indivisible
Greek Origin
Meaning
Key Words
atomos
Cannot be cut; indivisible
Atom, atomic number,
atomic mass

13. Greek Word Origins beta Second letter of the Greek alphabet
Greek Origin
Meaning
Key Words
beta
Second letter of the Greek alphabet
Beta particle

14. Greek Word Origins di Two, double Diatomic molecule Greek Origin
Meaning
Key Words di
Two, double
Diatomic molecule

15. Greek Word Origins gamma Third letter of the Greek alphabet
Greek Origin
Meaning
Key Words
Third letter of the Greek alphabet
gamma
Gamma radiation

16. Greek Word Origins hals Salt, relating to salt Halogen Greek Origin
Meaning
Key Words
hals
Salt, relating to salt
Halogen

17. Apply It!
Review the Greek origins and meanings in the chart. What is the
meaning of the prefix di- in diatomic? Predict the meaning of
diatomic molecule. Revise your definition as needed.
Sample: Since diatomos means “two atoms,” di- probably means “two.”

18. End of Chapter Preview

19. Section 1: Introduction to Atoms
How did atomic theory develop and change?
What is the modern model of the atom?

20. Atomic Theory and Models
Dalton thought that atoms were like smooth, hard balls that could not be broken into smaller pieces.

21. Atomic Theory and Models
Thomson suggested that atoms had negatively charged electrons embedded in a positive sphere.

22. Rutherford’s Gold Foil Experiment
Rutherford was surprised that a few particles were deflected strongly. This led him to propose an atomic model with a positively charged nucleus.

23. Later Atomic Models
Through the first part of the twentieth century, atomic models continued to change.

24. Modern Model of an Atom
This model of a carbon atom consists of positively charged protons and neutral neutrons in a nucleus that is surrounded by a cloud of negatively charged electrons.

25. Particles in an Atom
An atom is composed of positively charged protons, neutral neutrons, and negatively charged electrons. Protons and neutrons are about equal in mass. An electron has about 1/2,000 the mass of a proton or neutron.

26. Isotopes
Atoms of all isotopes of carbon contain six protons and six electrons, but they differ in their number of neutrons. Carbon-12 is the most common isotope.

27. More on Atomic Structure
Click the PHSchool.com button for an activity about atomic structure.

28. End of Section: Introduction to Atoms

29. Section 2: Organizing the Elements
How did Mendeleev discover the pattern that led to the periodic table?
How are the elements organized in the modern periodictable?

30. The Periodic Table
Elements are organized into rows and columns based on their atomic number.

31. The Periodic Table
Elements are organized into rows and columns based on their atomic number.

32. The Periodic Table
Elements are organized into rows and columns based on their atomic number.

33. Periodic Table Activity
Click the Active Art button to open a browser window and access Active Art about the periodic table.

34. Finding Data on Elements
Each square in the periodic table lists four pieces of information: an element’s atomic number, chemical symbol, name, and atomic mass.

35. End of Section: Organizing the Elements

36. Section 3: Metals What are the physical properties of metals?
How does the reactivity of metals change across the periodic table?
How are synthetic elements produced?

37. Metals in the Periodic Table
The metals in Group 1, from lithium to francium, are called the alkali metals. Alkali metals react with atoms of other elements by losing one electron.

38. Metals in the Periodic Table
Group 2 of the periodic table contains the alkaline earth metals. These elements are not as reactive as the metals in Group 1, but they are more reactive than most other metals.

39. Melting Points in a Group of Elements
The properties of elements within a single group in the periodic table often vary in a certain pattern. The following graph shows the melting points of Group 1 elements (alkali metals) from lithium to francium.

40. Melting Points in a Group of Elements
Reading Graphs:
As you look at Group 1 from lithium to francium, describe how the melting points of the alkali metals change.
Melting points decrease from lithium to francium.

41. Melting Points in a Group of Elements
Predicting:
If element number 119 were synthesized, it would fall below francium in Group 1 of the periodic table. Predict the approximate melting point of new element 119.
New element 119 should have a melting point of approximately 25ºC or lower.

42. Melting Points in a Group of Elements
Interpreting Data:
Which of the alkali metals are liquids at 35ºC?
Cesium, francium

43. Metals in the Periodic Table
The transition metals are less reactive than the metals in Groups 1 and 2.

44. Metals in the Periodic Table
Only some of the elements in Groups 13 through 15 of the periodic table are metals.

45. Metals in the Periodic Table
Lanthanides are usually found together in nature, always combined with other elements.

46. Metals in the Periodic Table
The elements below the lanthanides are called actinides. Many of these elements are so unstable that they last for only a fraction of a second after they are made.

47. Click the SciLinks button for links on metals.

48. End of Section: Metals

49. Section 4: Nonmetals, Inert Gases, and Semimetals
What are the properties of nonmetals and inert gases?
How are semimetals useful?

50. Properties of Nonmetals
When nonmetals and metals react, electrons move from the metal atoms to the nonmetal atoms.

51. Families of Nonmetals
Each element in the carbon family has atoms that can gain, lose, or share four electrons when reacting with other elements.

52. Families of Nonmetals
Group 15, the nitrogen family, contains two nonmetals: nitrogen and phosphorus. These non-metals usually gain or share three electrons when reacting with other elements.

53. Families of Nonmetals
Group 16, the oxygen family, contains three nonmetals: oxygen, sulfur, and selenium. These elements usually gain or share two electrons when reacting with other elements.

54. Families of Nonmetals
The Group 17 elements, the halogens, are very reactive. Atoms of these elements easily form compounds by sharing or gaining one electron when reacting with atoms of other elements.

55. Families of Nonmetals
The elements in Group 18 are the inert gases. They do not ordinarily form compounds because atoms of inert gases do not usually gain, lose, or share electrons.

56. Families of Nonmetals
Because the chemical properties of hydrogen differ very much from those of the other elements, it really cannot be grouped into a family.

57. Semimetals
The most useful property of the semimetals is their varying ability to conduct electric current.

58. Click the SciLinks button for links on nonmetals.

59. End of Section: Nonmetals, Inert Gases, and Semimetals

60. Section 5: Radioactive Elements
How was radioactivity discovered?
What types of particles and energy can radioactive decay produce?
In what ways are radioactive isotopes useful?

61. Types of Radioactive Decay
During alpha decay, a nucleus loses an alpha particle, which consists of two protons and two neutrons.

62. Types of Radioactive Decay
During beta decay, a neutron inside an unstable nucleus changes into a negatively charged beta particle and a proton.

63. Types of Radioactive Decay
Gamma radiation has no charge and does not cause a change in either the atomic mass or the atomic number.

64. Types of Radioactive Decay
The three types of nuclear radiation were named based on how easily each one could be blocked. Alpha, beta, and gamma are the first three letters of the Greek alphabet.

65. Using Radioactive Isotopes
Tracers are radioactive isotopes that can be followed through the steps of a chemical reaction or industrial process.

66. Radioactive Tracers Activity
Click the Active Art button to open a browser window and access Active Art about radioactive tracers.

67. Click the Video button to watch a movie about radiation.

68. End of Section: Radioactive Elements

69. QuickTake Quiz
Click to start quiz.