1. Table of Contents Introduction to Atoms Organizing the Elements Metals
Nonmetals and Metalloids
Elements From Stardust

2. Structure of an Atom - Introduction to Atoms
A carbon atom consists of protons and neutrons in a nucleus that is surrounded by electrons.

3. Models of Atoms - Introduction to Atoms
For over two centuries, scientists have created models of atoms in an effort to understand why matter behaves as it does. As scientists have learned more, the model of the atom has changed.

4. Isotopes - Introduction to Atoms
Atoms of all isotopes of carbon contain six protons, but they differ in the number of neutrons. Carbon-12 is the most common isotope.

5. Previewing Visuals - Introduction to Atoms
Before you read, preview Figure 2. Then write two questions that you have about the diagram in a graphic organizer like the one below. As you read, answer your questions.
Structure of an Atom
Q. What particles are in the center of the atom?
A. Protons and neutrons
Q. What particles move around the outside of the nucleus?
A. Electrons

6. Click the PHSchool.com button for an activity about atoms.
- Introduction to Atoms
More on Atoms
Click the PHSchool.com button for an activity about atoms.

7. End of Section: Introduction to Atoms

8. Finding Data on Elements
- Organizing the Elements
Finding Data on Elements
Each square of the periodic table includes an element’s atomic number, chemical symbol, name, and atomic mass.

9. Periodic Table Activity
- Organizing the Elements
Periodic Table Activity
Click the Active Art button to open a browser window and access Active Art about the periodic table.

10. Organization of the Periodic Table
- Organizing the Elements
Organization of the Periodic Table
The 18 columns of the periodic table reflect a repeating pattern of properties that generally occur across a period.

11. Asking Questions - Organizing the Elements
Before you read, preview the red headings. In a graphic organizer like the one below, ask a what or how question for each heading. As you read, write answers to your questions.
Question
Answers
What pattern of elements did Mendeleev discover?
Patterns appeared when the elements were arranged in order of increasing atomic mass.
What data about elements is found in the periodic table?
Atomic number, chemical symbols and names, and average atomic mass
How are elements organized in the periodic table?
Elements are organized in periods and groups based on their properties.

12. End of Section: Organizing the Elements

13. 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.

14. 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.

15. Melting Points in a Group of Elements
- Metals
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.

16. Melting Points in a Group of Elements
- Metals
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.

17. Melting Points in a Group of Elements
- Metals
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.

18. Melting Points in a Group of Elements
- Metals
Melting Points in a Group of Elements
Interpreting Data:
Room temperature is usually about 22ºC. Human body temperature is 27ºC. Which of the alkali metals are liquids at room temperature? Which might melt if you could hold them in your hand?
None of the alkali metals are liquids at room temperature. Cesium and francium might melt if you could hold them in your hand.

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

20. Metals in the Periodic Table
Only some of the elements in Groups 13 through 15 of the periodic table are metals. These metals are not nearly as reactive as those on the left side of the table.

21. Metals in the Periodic Table
Lanthanides are soft, malleable, shiny metals with high conductivity.

22. 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.

23. Using Prior Knowledge - Metals
Before you read, write what you know about metals in a graphic organizer like the one below. As you read, write what you learn.
What You Know
Metals are shiny.
Some metals are magnetic.
What You Learned
Ductile metals can be pulled into a wire.
Alkali metals react by losing one electron.

24. Click the SciLinks button for links on metals.

25. End of Section: Metals

26. Properties of Nonmetals
- Nonmetals and Metalloids
Properties of Nonmetals
When nonmetals react with metals, one or more electrons move from the metal atoms to the nonmetal atoms.

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

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

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

30. Families of Nonmetals - Nonmetals and Metalloids
The Group 17 elements are the most reactive nonmetals. Atoms of these elements easily form compounds by sharing or gaining one electron when reacting with atoms of other elements.

31. Families of Nonmetals - Nonmetals and Metalloids
The elements in Group 18 are known as the noble gases. They do not ordinarily form compounds because atoms of noble gases do not usually gain, lose, or share electrons.

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

33. The Metalloids - Nonmetals and Metalloids
The metalloids have some characteristics of both metals and nonmetals. The most useful property of the metalloids is their varying ability to conduct electricity.

34. Using Prior Knowledge - Nonmetals and Metalloids
Before you read, write what you know about nonmetals in a graphic organizer like the one below. As you read, write what you learn.
What You Know
Nonmetals are not shiny.
Nonmetals are not magnetic.
What You Learned
Nonmetals are dull and brittle.
Metalloids have characteristics of metals and nonmetals.

35. Click the SciLinks button for links on nonmetals.
- Nonmetals and Metalloids
Links on Nonmetals
Click the SciLinks button for links on nonmetals.

36. End of Section: Nonmetals and Metalloids

37. How Elements Form in Stars
- Elements From Stardust
How Elements Form in Stars
Nuclear fusion, which occurs in stars on a huge scale, combines smaller nuclei into larger nuclei, creating heavier elements.

38. Sequencing - Elements From Stardust
As you read, make a flowchart like the one below that shows how elements are formed in stars. Write the steps in separate boxes in the flowchart in the order in which they occur.
Hydrogen nuclei fuse, forming helium.
Helium nuclei fuse, forming beryllium.
Fusion continues in smaller stars, forming elements up to oxygen.
Fusion in larger stars produces heavier elements up to iron.
The heaviest elements form during supernova explosions of the most massive stars.

39. Links on Nuclear Fusion
- Elements From Stardust
Links on Nuclear Fusion
Click the SciLinks button for links on nuclear fusion.

40. End of Section: Elements From Stardust

41. Patterns of properties
Graphic Organizer
Periodic table
is made up of
organizes
Elements
Rows
Columns
in order of increasing
called
called
Atomic
number
Periods
Families
and shows or
Patterns of properties
Groups

42. End of Section: Graphic Organizer