How are most library books classified?

1. How are most library books classified? Why is such a classification system useful?

2. Chapter 6 and 7 The Periodic Table and Periodic LawHarry Potter Sings the Element SongJim Lehrer The Real Periodic Table Song

3. 1789 - Lavoisier Acid making Gas like sulfur light phosphorous heat oxygen carbon Azote (nitrogen) hydrogen

4. 1789 - Lavoisier Metallic Earthy Cobalt, mercury, tin Lime (calcium hydroxide) Copper, nickel, iron Magnesia(magnesium oxide) Barytes (barium sulphate) Gold, lead, silver, zinc Manganese, tungsten Argilla (Aluminum oxide) (platina) platinum Silex (silicon dioxide)

5. I. Development of the Modern Periodic Table 6.1 pg. 151-158 A. Lavoisier – 1790’s • 1. Compiled a list of 23 elements known at the time. • 2. 1800’s: changes in the world • 3. Electricity used to break compounds, spectrometer, industrial revolution • 4. Tripled Lavoisier’s number of elements • 5. 1860 chemists agreed on atomic masses

6. B. John Newland - 1864 • 1. Proposed an organization scheme • 2. Arranged by increasing atomic mass • 3. The elements’ properties repeated every eighthelement • 4. The law of octaves. Musical Analogy

7. B. John Newland - 1864

8. C. Meyer, Mendeleev, & Moseley • 1. Meyer & Mendeleev each demonstrated connections between atomic mass and elemental properties. • 2. Mendeleev published first and showed the connections’ usefulness • 3. Mendeleev predicted the existence and properties of undiscovered elements. • 4. He left blanks for undiscovered elements • Can you find the errors in his system?

9. C. Meyer, Mendeleev, & Moseley

10. BBC History of the Periodic Table

11. Mendeleev’s First Periodic Table "...if all the elements be arranged in order of their atomic weights a periodic repetition of properties is obtained." - Mendeleev

12. 5. Henry Moseley (1913): British chemist - discoveries resulted in a more accurate positioning of elements by determination of atomic numbers. (Tragically for the development of science, Moseley was killed in action at Gallipoli in 1915).

13. 5. Moseley (continued) 5. When atoms were arranged according toincreasing atomic number, the few problems with Mendeleev's periodic table had disappeared. Because of Moseley's work, the modern periodic table is based on the atomic numbers of the elements 6. Periodic Law: There is a periodic repetition of the chemical and physical properties of the elements when they are arranged by increasing atomic number.

14. 5. Moseley

15. II. The Modern Periodic Table

16. II. The Modern Periodic Table • A.Columns on the periodic table are called groups or families. • Atomic number increases as you move down on the periodic table. • Each group is numbered one though eight, followed by the letter A or B. What group is Chlorine in? VIIA

17. II. The Modern Periodic Table • B. The rows on the periodic table are called periods. • Each row on periodic table (except the first) begins with a metal and ends with a noble gas. • Beginning with hydrogen in period 1 there are a total of seven periods. In between, the properties of the elements change in an orderly progression from left to right. • The pattern in properties repeats after group VIIIA (18).

18. II. The Modern Periodic Table • C. Why does the first period on the periodic table only have two elements? • Only two electrons can occupy the first energy level in an atom. • The third electron in lithium must be at a higher energy level. • Lithium is the first element in Group IA and in Period 2.

19. II. The Modern Periodic Table • D. The groups designated with an A (IA through VIIIA) are often referred to as the main group or representative elements because they possess a wide range of chemical and physical properties. • The groups designated with a B (IB through VIIIB) are referred to as the transition elements.

20. II. The Modern Periodic Table • Vanadium a transition element.

21. III. Classification of the Elements • Valence Electrons • electrons in the highest principal energy level • What would group IA look like? 1s1, 2s1…. 3. Atoms in the same group have similarchemical properties because they have the same number of valence electrons. B. The s-, p-, d- and f- block elements

22. III. Classification of the Elements

23. IV. Classification of the Elements A. Metals are elements that have luster, conduct heat and electricity, and usually bend without breaking, and are solid at room temperature. With the exception of tin, lead, and bismuth, metals have one, two, or three valence electrons.

24. The Metals

25. IV. Classification of the Elements • Metals are to the left of the heavy stair-step line that zigzags down from Boron (B, in column IIIA) to astatine (At) at the bottom of group VIIA (hydrogen is the exception). • Alkali metals – group IA, the most reactive of all metals. They react with water to form alkaline solutions.

26. Alkali metals

27. IV. Classification of the Elements • Alkaline earth metals group IIA. These elements form compounds with oxygen, called oxides. • All transition elements are metals.

28. IV. Classification of the Elements • All transition elements are metals.

29. IV. Classification of the Elements • Inner transition metals are know as lanthanide and actinide series and are located along the bottom of the periodic table. Because of their natural abundance on Earth is less than 0.01 percent, the lanthanides are sometimes called the rare earth elements. All of the lanthanides have similar properties.

30. IV. Classification of the Elements • All of the actinides are radioactive, and none beyond uranium (92) occur in nature.

31. Dr. Glenn Seaborg on Transuranium Elements Meet Dr. Glenn Seaborg 0:59-4:43

32. III. Classification of the Elements B. Nonmetals are elements that are generally gases or brittle, dull-looking solids. They are poor conductors of heat and electricity. • The only liquid nonmetal at room temperature is bromine (Br). • The highly reactive group VIIA is the halogens, “salt formers.” The extremely un-reactive group is the noble gases. • The nonmetals oxygen and nitrogen make up 99 percent of Earth’s atmosphere.

33. III. Classification of the Elements • Carbon, another nonmetal, is found in more compounds than all the other elements combined. • Their melting points tend to be lower than those of metals.

35. III. Classification of the Elements C. Metalloids or semimetals. Metalloids are elements with physical and chemical properties of both metals and nonmetals. Silicon and germanium are two of the most important metalloids as they are used extensively in computer chips and solar cells.

36. III. Classification of the Elements • Some metalloids such as silicon, germanium (Ge), and arsenic (As) are semiconductors.

37. III. Classification of the Elements • A semiconductor is an element that does not conduct electricity as well as a metal, but does conduct slightly better than a nonmetal. • The ability of a semiconductor to conduct an electrical current can be increased by adding a small amount of certain other elements.

38. III. Classification of the Elements • Silicon’s semi conducting properties made the computer revolution possible. • Your television, computer, handheld electronic games, and calculator are electrical devices that depend on silicon semiconductors.

39. III. Classification of the Elements • All have miniature electrical circuits that use silicon’s properties as a semiconductor. • You learned that metals generally are good conductors of electricity, nonmetals are poor conductors, and semiconductors fall in between the two extremes.

40. III. Classification of the Elements • The ability of a semiconductor to conduct an electrical current can be increased by adding a small amount of certain other elements. • Silicon’s semi conducting properties made the computer revolution possible. • Your television, computer, handheld electronic games, and calculator are electrical devices that depend on silicon semiconductors.

41. III. semiconductors Awesome New Technology – Cool Gadgets

42. What clues does the arrangement of the football players on the field give about the functions of their positions?

43. What characteristics does a football player have based on the position played?

44. V. Periodic Trends 6.3 pgs. 163-169 • A. Atomic Size or Radius • How closely an atom lies to a neighboring atom. • Metals – half the distance between two adjacent atoms in a crystal • Nonmetal – determined from a diatomic molecule of an element

45. Time out! What’s a diatomic element?

46. an element that when not chemically bonded with any other elements, will form a molecule having two atoms of the element. • Time out! What’s a diatomic element? N2, H2, F2… Mr. Brinklehoff BrINClHOF gases

47. A. Atomic Radii - trend (cont.) • Size increases going across – right to left. (Across same energy level, but add protons and the ‘pull’ of nucleus is greater and pulls electrons closer.) • Size increases going down a group. Electrons are at progressively higher levels, and shielding effect is increasing.

48. A. Atomic Radii (continued) • Shielding Effect – lots of inner electrons shield or protect the outer electrons from the ‘pull’ of the positive nucleus. • What happens to shielding effect as you go down the periodic table? increases • What happens to shielding effect as you go across the periodic table? Stays the same Quick time video

49. B. Ionic Radius • Positive ions are alwayssmallerthan neutral atoms +1 +2 +3 • Negative ions are alwayslargerthan neutral atoms because their nuclear attraction is less -3 -2 -1

50. Going down a group – both anions and cations get bigger Going across: + decrease, - increase Smaller Larger