1. The Periodic Table Copyright © 2008 by Pearson Education, Inc.
Publishing as Benjamin Cummings

2. Groups and Periods On the periodic table
Elements are arranged by increasing atomic number and according to similar properties.
Groups contain elements with similar properties in vertical columns.
Periods are horizontal rows of elements.

3. Groups and Periods Copyright © 2008 by Pearson Education, Inc.
Publishing as Benjamin Cummings

4. Periodic Table
Inner Transition Metals

5. Group Numbers Group Numbers
Use the letter A for the representative elements 1A to 8A and the letter B for the transition elements.
Also use numbers 1-18 for the columns from left to right.

6. Names of Some Representative Elements
Several groups of representative elements are known by common names.
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

7. Alkali Metals
Group 1A(1), the alkali metals, includes lithium, sodium, and potassium. All have 1 valence electron and form 1+ ions.

8. Alkaline Earth Metals Include: Beryllium Magnesium Calcium Strontium
Barium
All are chemically reactive due to their outermost energy level having 2 electrons.
Form 2+ ions when reacting with non-metals.

9. Halogens Group 7A(17) the halogens, includes chlorine, bromine, and
iodine.
All have 7 valence electrons.
Form 1- ions when reacting with metals.
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Publishing as Benjamin Cummings

10. Noble Gases Are chemically unreactive. Include: Helium
All, but He, have 8 valence electrons.
Mr. Queen’s favorite group!
Include:
Helium
Neon
Argon
Krypton
Xenon
Radon

11. Learning Check Identify the element described by the following:
A. Group 7A(17), Period 4
1) Br 2) Cl ) Mn
B. Group 2A(2), Period 3
1) beryllium 2) magnesium 3) boron
C. Group 5A(15), Period 2
1) phosphorus 2) arsenic ) nitrogen

12. Solution A. Group 7A(17), Period 4 1) Br B. Group 2A(2), Period 3
2) magnesium
C. Group 5A(15), Period 2
3) nitrogen

13. Metals, Nonmetals, and Metalloids
The heavy zigzag line
separates metals and
nonmetals.
Metals are located to the left.
Nonmetals are located to the right.
Metalloids are located along the heavy zigzag line between the metals and nonmetals.
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Publishing as Benjamin Cummings

14. Properties of Metals, Nonmetals, and Metalloids
Are shiny and ductile.
Are good conductors of heat and electricity.
Nonmetals
Are dull, brittle, and poor conductors.
Are good insulators.
Metalloids
Are better conductors than nonmetals, but not as good as metals.
Are used as semiconductors and insulators.

15. Comparing A Metal, Metalloid, and Nonmetal
Table 4.3
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16. Learning Check Identify each of the following elements as
1) metal 2) nonmetal ) metalloid
A. sodium ____
B. chlorine ____
C. silicon ____
D. iron ____
E. carbon ____

17. Solution Identify each of the following elements as
1) metal 2) nonmetal ) metalloid
A. sodium 1 metal
B. chlorine 2 nonmetal
C. silicon 3 metalloid
D. iron 1 metal
E. carbon 2 nonmetal

18. Learning Check Match the elements to the description:
A. Metals in Group 4A(14)
1) Sn, Pb ) C, Si ) C, Si, Ge, Sn
B. Nonmetals in Group 5A(15)
1) As, Sb, Bi ) N, P 3) N, P, As, Sb
C. Metalloids in Group 4A(14)
1) C, Si, Ge, ) Si, Ge ) Si, Ge, Sn, Pb

19. Solution Match the elements to the description:
A. Metals in Group 4A (14)
1) Sn, Pb
B. Nonmetals in Group 5A(15)
2) N, P
C. Metalloids in Group 4A(14)
2) Si, Ge

20. Energy Levels Principal Energy levels
Are assigned numbers n = 1, 2, 3, 4 and so on.
Increase in energy as n increases.
Are like the rungs of a ladder with the lower energy levels nearer the nucleus.
n = 4
n = 3
n = 2
n = 1

21. Electron Capacity of Energy Levels
Capacity of Principal Energy Levels
1st: 2 electrons
2nd:8 electrons
3rd: 18 electrons (but stable with 8)
4th: 32 electrons (but stable with 8)

22. Valence Electrons Valence electrons
Determine the chemical properties of the elements.
Are the electrons in the highest energy level.
Are related to the Group number of the element.
Example: Phosphorus has 5 valence electrons
5 valence electrons
P Group 5A(15) , 8, 5

23. Groups and Valence Electrons
All the elements in a group have the same
number of valence electrons.
Example: Elements in Group 2A(2) have two (2) valence electrons.
Be 2, 2
Mg 2, 8, 2
Ca 2, 8, 8, 2
Sr 2, 8, 18, 8, 2

24. Periodic Table and Valence Electrons
Representative Elements Group Numbers
H He
Li Be Al C N O F Ne
2,1 2, , , , , , ,8
Li Mg Ge Si P S Cl Ar
2,8,1 2,8,2 2,8,3 2,8,4 2,8,5 2,8,6 2,8,7 2,8,8

25. Learning Check State the number of valence electrons for each: A. O
1) ) 6 3) 8
B. Al
1) ) 3 3) 1
C. Cl
1) 2 2) 5 3) 7

26. Solution State the number of valence electrons for each. A. O 2) 6
2) 6
B. Al
2) 3
C. Cl
3) 7

27. Atomic Size Atomic radius
Is the distance from the nucleus to the valence electrons.
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28. Atomic Radius Within A Group
Atomic radius increases
Going down each group of representative elements.
As the number of energy levels with electrons increases.
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Publishing as Benjamin Cummings

29. Atomic Radius Across a Period
Atomic radius decreases
Going from left to right across a period.
As more protons increase effective nuclear attraction for valence electrons.
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

30. Learning Check Select the element in each pair with the larger
atomic radius.
A. Li or K
B. K or Br
C. P or Cl
Solution: A. K B. K C. P