The Periodic Table

1. The Periodic Table

2. PERIODIC • appearing or occurring at intervals. • Why is it labeled the Periodic Table? • Name some things that are periodic: • It is periodic because there are patterns that repeat each row or period.

3. A BRIEF HISTORY We have not always had the periodic table. The modern table as we know it is only about 100 years old.

4. A BRIEF HISTORY Father of the Periodic Table DMITRI MENDELEEV published 1869. • He discovered a basic chemistry principle. • He felt there was a certain pattern with the elements. - He tested his hypothesis that there was a periodic relationship among the elements. - He set up the periodic table by ATOMICMASSand left blanks for undiscoveredelements (three were later discovered).

5. MENDELEEV’S TABLE

6. A BRIEF HISTORY Father of the Modern Periodic Table HENRY MOSELEY 1913 - He saw some elements were out of place in Mendeleev’s table. • He determined atomic numbers using x-rays. • The elements were placed according to ATOMIC NUMBER. This was an important change. - This is the modernperiodic table.

7. A BRIEF HISTORY The Final Changes to the Table Glenn Seaborg • The last major change to the periodic table resulted from Glenn Seaborg's work. • Starting with plutonium in 1940, Seaborg discovered transuranium elements 94 to 102 and reconfigured the periodic table by placing the lanthanide/actinide series at the bottom of the table. • In 1951 Seaborg was awarded the Nobel Prize in chemistry and element 106 was later named seaborgium (Sg) in his honor.

8. Seaborg’s Contribution

9. WATCH • The Genius of Dmitri Mendeleev

10. PERIODIC TABLE ORGANIZATION Columns - vertical, called groups (numbers) or families (names) - 18 total (8 main ones) - elements in the same column are not identical, but similar in properties.

12. PERIODIC TABLE ORGANIZATION ROWS • horizontal, called periods, • 7 total (at this time) • elements are not alike in any way PATTERN: left side elements are active solids, far right side elements are inert (nonreactive) gases. Last two rows are rare earth elements. Atomic number increases from left to right.

13. 1 2 3 4 5 6 7 6 7

14. ALTERNATIVE PERIODIC TABLES: SPIRAL

15. ALTERNATIVE PERIODIC TABLES:STOWE

16. ALTERNATIVE PERIODIC TABLES:TARANTOLA

17. ALTERNATIVE PERIODIC TABLES:MURADJAN

18. ALTERNATIVE PERIODIC TABLES: CHEMICAL GALAXY

19. ALTERNATIVE PERIODIC TABLES: 3D

20. CHARACTERISTICS OF THE PERIODIC TABLE • Gases: hydrogen, helium, nitrogen, oxygen, fluorine, chlorine, neon, argon, krypton, xenon, radon. • Liquids: mercury, bromine • Solids: all the rest

21. PERIODIC TABLE • Number the groups 1-18. • Number the periods 1-7. • Find element 92 (fourth one from the left in the bottom most row). • Outline or lightly shade the elements that appear AFTER it in the row. • Find the seventh period in the main table. Outline or lightly shade the elements that appear AFTER the first two in the row.

23. PERIODIC TABLE • You have just outlined the synthetic elements, • artificial elements, called the transuranium elements (“After” uranium). • These are made in particle accelerators.

24. VALENCE ELECTRONS •  The valence electronsare the electrons in the outermost shell or energy level of an atom. • The valence electrons are the ones involved in forming bondsto adjacent atoms. • Therefore, the number of valence electrons is important for determining the numberof bonds an atom will form.

25. VALENCE ELECTRONS Group 1 1 valence electrons Group 2 2 valence electrons Group 13 3 valence electrons Group 14 4 valence electrons Group 15 5 valence electrons Group 16 6 valence electrons Group 17 7 valence electrons Group 18 8 valence electrons

26. VALENCE ELECTRONS

27. VALENCE AND ELECTRON DOT DIAGRAMS • Valence electrons = electrons in outermost energy level of a BohrDiagram. • Electrons in outermost energy level of a Bohr Diagram = electrons in electron dot diagram SO • Valence electrons = electrons in electron dot diagram

29. VALENCE AND ELECTRON DOT DIAGRAMS

30. We will look at how to draw electron dot diagram Wednesday. • Skip the last column if you need to for now.

31. ANOTHER WAY TO LOOK AT THE TABLE All elements can be divided into three groups: METALS NONMETALS METALLOIDS

32. METALS

33. METALS • located on the left side and center. • good conductors of heat and electricity. • hard and shiny (not always silver) • can be pounded into different shapes - malleable • can be drawn into a wire - ductile • high density, high melting points • react with water and substances in the atmosphere (ex. rusting, tarnishing)

34. METALS • has only a few electrons in the outer level • most elements are metals. • General rule: 3 or fewer electrons in outer level are considered to be metals. • Metals have a tendency to lose electrons when forming compounds.

35. NONMETALS

36. NONMETALS • located on the right side (except hydrogen) • poor conductors of heat and electricity (solids are insulators) • brittle solids or gases or liquids • dull • shatter easily • lower density, lower melting points

37. NONMETALS • not as easy to recognize as a group • has more than 4 electrons in the outer level. • General rule: 5 or more electrons in outer level are considered to be nonmetals. • Nonmetals have a tendency to gain electrons when forming compounds

38. METALLOIDS

39. METALLOIDS • Sometimes called semi-metals. • have properties of metals and nonmetals • “metal-like” • located on either side of the staircase • all are shiny, white-gray in color • all are solids • okay conductors (as in semi-conductors), ductile, malleable

40. METALLOIDS There are seven: Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Astatine Aluminum is NOT a metalloid. Polonium is sometimes classified as a metalloid.

41. METALLOIDS

42. UNKNOWN METALS LAB Introduction: Most of the elements on the periodic table are metals and solids. These elements have observable properties that make it possible to identify an unknown element. Density is one of the properties that can be used to identify an unknown metal. As you know, density is the ratio of mass to volume. In equation form: Density = Mass ÷ Volume.

43. THE ELEMENT FAMILIES

44. HYDROGEN – a special case • one valence electron • Considered a nonmetal; • Not part of Group One; • acts as a metal and a nonmetal; • most abundant element in the universe; • flammable

45. ALKALI METALS – group 1

46. GROUP 1: ALKALI METALS • Early in human history, people discovered that ashes mixed with water produced a slippery solution useful for removing grease. • By the Middle Ages, such mixtures were described as alkaline, a term derived from the Arab word for ashes, al-qali. • Alkaline mixtures found many uses, particularly in the preparation of soaps. • This is why they are called alkali metals. • We now know that alkaline ashes contain compounds of Group 1 elements, most notably potassium carbonate (potash).

47. ALKALI METALS – group one • one valence electron; • very reactive • Most reactive is francium; • not found in nature by themselves; • low electron affinity • SODIUM and POTASSIUM important to body functions • FRANCIUM – most reactive metal, but extremely rare

48. GROUP TWO:ALKALINE EARTH METALS

49. ALKALINE EARTH METALS – group two • Elements in group 2 also form alkali solutions when placed in water. • Medieval alchemists noted that certain minerals do not melt or change when put into fire – we know these as group 2 elements. • These fire-resistant substances were known to alchemists as earth. As a holdover from these ancient times, group 2 elements are known as alkaline earth metals.

50. ALKALINE EARTH METALS – group two • two valence electrons; • less reactive, but similar to alkali metals; • low electron affinity, • CALCIUM – 5th most abundant element on earth (lime, calcium chloride, body functions)