1. Chapter 3- Understanding the
7th Grade
Chapter 3- Understanding the
Periodic Table

2. Chapter 3- Understanding the Periodic Table
7th Grade Science
Chapter 3- Understanding the
Periodic Table
PISD PowerPoint Lessons
Developed By
Ryan Gross, Park Crest Middle School
Edited By
Kenn Heydrick, Coordinator of Science & Health

3. Chapter 3 - Understanding the Periodic Table
Section 1:
Electrons and the Periodic Table
Section 2:
Grouping the Elements
Unit A: Chapter 3

4. Why Do I Need the Periodic Table?
What Do You Think?
What does your outer shell of clothing say to other people about you and who you are?
Unit A: Chapter 3

5. Electrons & the Periodic Table
Electrons in all atoms are arranged around the nucleus in regions called energy levels
The largest atoms have as many as seven energy levels
Energy Levels
Unit A: Chapter 3

6. Electrons & the Periodic Table
The outermost energy level is called the valence shell
The electrons in the valence shell are called valence electrons
Energy Levels
Unit A: Chapter 3

7. Electrons & the Periodic Table
Elements are grouped because they have similar properties
In some groups, the elements all have the same number of valence electrons in their atoms
Unit A: Chapter 3

8. Electrons & the Periodic Table
In atoms of elements in Groups 1 & 2, the number of valence electrons matches the group number
Unit A: Chapter 3

9. Electrons & the Periodic Table
In atoms of elements in Groups 13-18, the number of valence electrons is 10 fewer than the group number
Unit A: Chapter 3

10. Electrons & the Periodic Table
Atoms of elements in Groups 3-12, the Transition Metals, do not follow a general rule
In addition, helium atoms only have 2 valence electrons
Unit A: Chapter 3

11. Why Do I Need the Periodic Table?
What Do You Think?
What similarities exist between you and the other members of your family? How about between you and your classmates?
Unit A: Chapter 3

12. Grouping the Elements - Group 1
Group 1: Alkali Metals-
1 Valence Electron
All metals except Hydrogen, the Group 1 elements, are the most reactive.
Unit A: Chapter 3

13. Grouping the Elements - Group 1
Group 1: Alkali Metals-
1 Valence Electron
This means that the atoms of these elements are not stable and will lend valence electrons to other atoms.
Unit A: Chapter 3

14. Grouping the Elements - Group 1
Group 1: Alkali Metals-
1 Valence Electron
These elements are never found uncombined in nature.
Unit A: Chapter 3

15. Grouping the Elements - Group 1
Alkali Metals
Compounds formed from Alkali metals have many uses for humans
NaCl, or Sodium Chloride, is table salt that is used to season your food
Potassium compounds are found in bananas
Unit A: Chapter 3

16. Grouping the Elements - Group 2
Group 2: Alkaline-Earth Metals- 2 Valence Electrons
Alkaline-Earth metals are very reactive, but not as reactive as Alkali metals.
Unit A: Chapter 3

17. Grouping the Elements - Group 2
Group 2: Alkaline-Earth Metals- 2 Valence Electrons
This is because it is harder for their atoms to lose 2 valence electrons than for the Alkali metals to lose 1
Unit A: Chapter 3

18. Grouping the Elements - Group 2
Group 2: Alkaline Earth Metals
Magnesium is mixed with other metals to make rims on cars.
Calcium is an important part of the compound that keeps your bones and teeth healthy.
Unit A: Chapter 3

19. Grouping the Elements Groups 3-12
Groups 3-12: Transition Metals
Groups 3-12 do not have individual names.
Unit A: Chapter 3

20. Groups 3-12 are all grouped together as the Transition Metals.
Unit A: Chapter 3

21. Groups 3-12
The Transition Metals are less reactive than Groups 1 & 2 because they don’t lose their valence electrons as easily.
Groups 3-12
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22. Silver and Gold are Transition Metals.
Grouping the Elements
Silver and Gold are Transition Metals.
Unit A: Chapter 3

23. Grouping the Elements
Transition Metals
Iron, Cobalt, and Nickel, all Transition Metals, are the only elements known to produce a magnetic field.
Unit A: Chapter 3

24. The most common element from Group 13 is aluminum.
Group 13: Boron Group
The most common element from Group 13 is aluminum.
Unit A: Chapter 3

25. Group 13
Aluminum was considered more precious than gold or silver until the 1880s, when plentiful electricity made it cheaper.
Aluminum is used to make cans, cars, and airplanes.
Unit A: Chapter 3

26. The nonmetal Carbon, in Group 14, is often found uncombined in nature.
Group 14: Carbon Group
The nonmetal Carbon, in Group 14, is often found uncombined in nature.
Unit A: Chapter 3

27. Carbon forms both diamonds and charcoal.
Group 14
Carbon forms both diamonds and charcoal.
Carbon also forms a wide variety of compounds such as proteins, fats, and carbohydrates, all necessary for life on earth.
Unit A: Chapter 3

28. Group 15
Group 15: Nitrogen Group
Nitrogen, a gas at room temperature, makes up about 78% of the air you breathe.
Unit A: Chapter 3

29. Nitrogen from the air is combined with Hydrogen to make fertilizer.
Group 15
Group 15: Nitrogen Group
Nitrogen from the air is combined with Hydrogen to make fertilizer.
Fertilizer helps grow the crops that feed us all.
Unit A: Chapter 3

30. Oxygen, in Group 16, makes up about 21% of the air you breathe.
Oxygen is very reactive, combining with many other elements such as iron and carbon.
Unit A: Chapter 3

31. Group 16
Sulfur, another common member of Group 16, is used to make sulfuric acid for car batteries.
Unit A: Chapter 3

32. Halogens are the very reactive nonmetals in Group 17.
They react easily because their atoms only need to gain 1 electron to have a complete set
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33. Group 17
Chlorine is a yellow halogen that is used to disinfect water for drinking and swimming
Unit A: Chapter 3

34. Noble gases are unreactive nonmetals in Group 18.
These elements’ atoms have full outermost energy levels, and cannot react with other elements
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35. Noble gases like neon glow when electrically charged.
Group 18
Noble gases like neon glow when electrically charged.
Argon in a light bulb keeps the filament from burning out.
Unit A: Chapter 3

36. Let’s Review!
1 -
How does the periodic table help you identify the physical properties of elements?
Unit A: Chapter 3

37. How are elements grouped on the periodic table of elements?
Let’s Review!
2 -
How are elements grouped on the periodic table of elements?
Unit A: Chapter 3