3.2 Using the Periodic Table

1. 3.2 Using the Periodic Table

2. Objectives • Relate an element’s valence electron structure to its position in the periodic table. • Use the periodic table to classify an element as a metal, nonmetal, or metalloid. • Compare the properties of metals, nonmetals, and metalloids.

3. New Vocabulary to Look for… • Period • Group • Noble gas • Metal • Transition element • Lanthanide • Actinide • Nonmetal • Metalloid • semiconductor

4. Relationship of the Periodic Table to Atomic Structure • Periodic tables contain a vast array of information on the elements. • You will learn to use the periodic table to gather information about the elements and group of elements we are studying. • Modern periodic table is arranged according to increasing atomic number. • What information does the atomic number tell us?

5. Periods and Groups • The horizontal rows of the periodic table are called periods. • The vertical columns are referred to as groups. • Groups are also called families of elements. • Elements in the same group have similar properties.

6. Atomic Structure of Elements Within a Period • Each period starts with a group 1 element, which has 1 valence electron. • As you move across a period the number of valence electrons increases. Moving from 1, 2, 13, 14, 15, 16, 17, 18. • Group 1 elements have one electron at a higher energy level than the noble gas of the preceding period.

7. Atomic Structure of Elements Within a Group • The number of valence electrons can be predicted using the periodic table. • Group 1 has 1 valence electron • Group 2 has 2 valence electrons • Groups 13-18 have the second digit of valence electrons. • 13 has 3 valence electrons • 14 has 4 valence electrons • Fig. 3.8 p. 98

8. Noble Gases • Group 18 have the periodic table. • They have 8 valence electrons, except for He which only has 2 • Full energy levels • Generally unreactive or inert • Ne, He, Ar

9. Noble Gases

10. Halogens • Greek meaning “salt former” • Form salt like compounds • Group 17 • 7 valence electrons • F, Cl, Br, I

11. Alkali Metal • Group 1 (except H) • 1 valence electron • Li, Na, K

12. Alkali Metals

13. Alkaline Earth Metals • Group 2 • 2 valence electrons • Be, Mg, Ca, Ba

14. Valence Electrons-Properties • Valence electrons help to determine the physical and chemical properties • Groups have similar properties b/c they have the same number of valence electrons • Fig. 3.9 p. 99 Electrons in Energy Levels-Group 16

15. Physical States and Classes of Elements

16. Physical States of the Elements • The physical states of the elements are show on the periodic table on p. 92-93. • Most elements are solids at room temperature • Only two are liquids. What are they? A. B. • All the gases except hydrogen are in the upper right corner of the table. List some.

17. Gallium

18. Classifying Elements • Elements are classified into groups • Metals • Nonmetals • Metalloids • Majority of elements are metals • Left side and center • Nonmetals • Upper right corner • Metalloids • Along the boundary b/t metals and nonmetals

19. Metals • Have luster • Conduct heat • Good conductors of electricity • Most have high boiling pts. • Malleable • Ductile • Most are solid • Only one metal is in the liquid state.

20. Metals • Most are located in Groups 1-13 • Transition Elements- Elements in Group 3-12 (all metals) • Iron (Fe), nickel (Ni), Copper (Cu), Zinc (Zn) • Some of period 7 are synthetic and radioactive • The transition elements have a less predictable behavior and properties than the other metals

21. Transition Elements

22. Transition Elements

23. Transition Elements

24. Metals • Elements with the atomic numbers 58-71 and 90-103 are placed below the main table • If they were part of the main table it would be extremely wide • Known as the inner transition elements • Many were unknown in Mendeleev’s time

25. Inner Transition Elements

26. Lanthanides • First series of inner transition elements • 14 elements 58-71 • Also called rare earth elements- abundance 0.01% • All have similar properties

27. Actinides • Second series of inner transition elements • 90-103 • Radioactive • None beyond uranium occur in nature • Unpredictable-complex structures

28. Nonmetals • Nonmetals are abundant in nature • Oxygen and nitrogen make up 99% of our atmosphere • Carbon is found in more compounds than all the other elements combined.

29. Nonmetals • Don’t conduct electricity • Poor conductors of heat • Brittle when solid • Many are gases at room temp. • Solids lack luster • Melting points and boiling points are low • Table 3.5 p. 105 Properties of Metals and Nonmetals

30. Metalloids • Have properties of both metals and nonmetals • Located between the metals and nonmetals • Si, Ge and As are semiconductor • Does not conduct electricity as well as a metal, but does better than a nonmetal • Si semiconductors made the computer revolution possible.

31. Atomic Structure of Metals, Metalloids and Nonmetals • Differences occur b/c of the different arrangements of electrons • Number, arrangement of valence electrons along with how tightly they are held in the atom determines the behavior.

32. Valence electrons in Metals • Loosely bound • Free to move in the solid metal • Easily lost • Freedom of movement = conductivity

33. Valence electrons in Nonmetals and Metalloids • Tightly held • Not easily lost

34. Chemical Reactions and Electrons • Metals tend to lose valence electrons • Nonmetals tend to share or gain electrons

35. General Properties and Uses of Metals, Nonmetals and Metalloids • Familiar Metals • Jewelry, figurines, electrical circuits • Some Lanthanides and Actinides • Compounds of europium and ytterbium – picture tubes of TV • Neodymium – high powered lasers • Carbon and Some Other Nonmetals • Carbon: Coal, natural gas, oil, graphite, diamonds • Bromine and Iodine – halogen lamps • Metalloids • Silicon – electronic devices • Page 106-107

37. Semiconductors • Metalloids that do not conduct electricity as well as metals, but better than nonmetals • Uses • Television • Computer • Handheld electronic games • Calculators

38. Semiconductors –Electrons and Electricity • An electrical current is flowing electrons. • Metals conduct electricity well because the electron are not tightly held by the nucleus and are therefore free to move. • Copper wire • At room temperature Si is not a good conductor. Its four electrons are tightly held by the nucleus. • In order to make it a good conductor it must be doped with another element.

39. Silicon (Si)

40. Doping of Si • By adding small amounts of P to Si a good conductor is created. • P has five valence electrons. This adds an extra electron which is free to move = electrical conductivity. • n-type semiconductor (negatively charged)

41. Doping of Si • By adding B to Si a good conductor is created • B has three valence electrons. The shortage of electrons creates “holes” in which the electrons can move = electrical conductivity. • p-type semiconductor (positively charged)

42. Diodes • The combination of n-type and p-type semiconductors is a diode. • Permits electrical flow in only one direction • Negative terminal to positive terminal

43. Transistors • Key components in electrical circuits, amplifying the electrical signal. • npn-junction • pnp-junction

44. Review • Where are the halogens, noble gases, alkali metals, alkaline earth metals, lanthanide and the actinides located? Give me an example of each? • What are the characteristics of a metal, nonmetal and metalloid? • How many valence electrons does Li have?

45. Using the Periodic Table