1. Periodic Trends
Section

2. Objectives
Review the characteristics in metals, nonmetals, and metalloids
Relate these characteristics to trends in atomic radius/ ionization energy/electron affinity

3. Key Terms
Metallic character
Nonmetallic character

4. Metals, Nonmetals, Metalloids

5. Metallic Character
Degree to which an element exhibits the physical and chemical properties of a metal.

6. Metals Lustrous, malleable, ductile, good conductors
All solids except liquid Hg

7. Metals LOW Ionization energy form positive ions easily
Ionization energy decreases as metallic character increases

8. Ionic Compounds Form between metal and nonmetal Metal oxides are bases
Metal oxide + H2O  metal hydroxide [7.9]
Ionizes in water, freeing up the metal and O
Metal oxide + acid  salt + H2O [7.12]

9. Nonmetals Dull, brittle, nonconductors (insulators).
Gases: H, N, O, F, Cl, noble gases
Liquid: Br
KNOW PHYSICAL STATES
OF ALL THE ELEMENTS!!

10. Nonmetals
HIGH electron affinities  gain electrons and become negative ions

11. Molecular Compound Nonmetals with nonmetals
Nonmetal oxides (CO2 or SO2) are acidic
The more nonmetallic= more acidic the oxide
Nonmetal oxide + H2O  acid [7.14]
No dissociation (molecular)
Nonmetal oxide + base  salt + H2O [7.16]

12. Metalloids Characteristics of both metals and nonmetals.
Shiny, brittle
All solids
Semiconductors
KNOW THEM!!

13. Overall Reactivity
The most reactive metals are the largest since they are the best electron givers.
The most reactive nonmetals are the smallest ones, the best electron takers.

14. Overall Reactivity

15. Homework 7.54 through 7.64 on page 294 EVENS only
Exclude part (a) of 7.56
Exclude part (c) of 7.62
Exclude part (d) of 7.64

16. Group Trends
Active Metals

17. Group Trends: Alkali Metals
ns1
Very reactive
Exist in nature only as compounds
Soft metallic solids
Na and K most abundant in Earth’s crust and biological systems
Physical properties: Table 7.4 on p. 281

18. Alkali Metals React with…
Hydrogen to form hydrides [7.17]
Sulfur to form sulfides [7.18]
H2O to form metal hydroxide and H2 [7.19]
Oxygen
Li forms metal oxide [7.20]
Na forms metal peroxide [7.21]
K, Rb, and Cs form superoxides [7.22]

19. The Alkaline Earth Metals
ns2
Solids
Harder and more dense than alkali
Table 7.5 on p. 285
Less reactive than alkali
Be and Mg are the least reactive

20. Alkaline Earth Metals Reactivity
Be does not react with water or steam
Mg does not react with water, reacts with steam
Mg(s) + H2O (g)  MgO(s) +H2 (g) [7.23]
All others react with water to form metal hydroxides and H2 [7.24]

21. The Alkaline Earth Metals
Heavier alkaline earth ions give off characteristic colors when heated
Ca = brick red
Sr = crimson red
Ba = green

22. The Alkaline Earth Metals
Mg and Ca essential to growth and maintenance of the human body
99% of Ca in body is in skeletal system

23. Group Trends
Selected Nonmetals

24. Hydrogen 1s1
Nonmetallic element in a class by itself- metallic inside the stars & Jovian planets
Most abundant element in the universe
Forms explosive mixtures with oxygen/halogens
Reacts with metals to form hydrides [7.17]
Loses it’s e- in H2O to form H+ ions

25. Chalcogens, ns2 np4 O, S, and Se are nonmetallic Te is a metalloid
Po is a radioactive, rare metal
Two allotropes of O (O2 and O3)
O is a great oxidizer
S has many allotropes
S8 is the most common
S reacts with almost every metal to form sulfides

26. Halogens, ns2,np5 Nonmetals Salt formers At is rare and radioactive
All very reactive; not found in free form.
Cl has the most industrial use
Reactivity: F2 > Cl2 > Br2 > I2

27. Noble Gases, ns2,np6 . Each of these elements has a full octet
Used to be the inert gases
They are all unreactive
Except XeF2, XeF4, XeF6 (Bartlett, 1962)
Recently  KrF2; HArF (stable at low temp)
He is commercially available-very expensive
Ar is more common-less than 1% of the air

28. Homework
on page 295
EVENS only
Not 7.68 b, c
Not 7.78 a

29. Balanced Reactions 7.17 (true for any metal) 7.9 7.18 7.12 7.19 7.14*
7.20
7.21
7.22
7.23
7.24
7.9
7.12
7.14*
7.16*
*Limited to any from the book, homework, or discussed in class