The Periodic Table. Bromfield Honors Chemistry

Transcription

1 The Periodic Table Bromfield Honors Chemistry

2 Write your answers in your notebook What is a trend? What are some patterns or trends you have observed?

3 Periodic Law Historical development Chemical Periodicity Periodic table Features of modern table Mendeleev Moseley Valence electrons Periods Groups Electronegativity Electron Configurations Alkali metals Atomic Size Ionic Size Periodic Trends Ionization Energy Electron Affinity Alkaline Earth Metals Transition Metals Chalcogens Halogens Noble Gases

4 Modern Periodic Table Periods horizontal rows Numbered 1-7 (corresponds to n)

5 Modern Periodic Table Groups vertical columns Numbered 1-18

6 Valence Electrons The outermost electrons in an atom

7 Valence Electrons The outermost electrons in an atom The electrons in the highest occupied s and p orbitals

8 Valence Electrons The outermost electrons in an atom The electrons in the highest occupied s and p orbitals Varies from 1 to 8

9 Valence Electrons The outermost electrons in an atom The electrons in the highest occupied s and p orbitals Varies from one to eight # of valence electrons = group number or group number - 10

10 How many valence electrons? Li C N Ar O Mg

11 Lewis dot diagrams One dot for each valence electron Li N O C Ar Mg

12 s, p, d and f blocks

13 Representative Elements Elements in the s and p blocks Aka Main group elements

14 Elements of the f block Often called the rare earths or inner transition metals Lanthanides Actinides Many are radioactive

15 Alternative Periodic Tables

16 Alternative Periodic Tables

17 Alternative Periodic Tables

18 Alternative Periodic Tables

19 Alternative Periodic Tables

20 Alternative Periodic Tables

21 Modern Periodic Table Video Most of the elements in the periodic table are metals!

22 Classes of elements Metals Typically solids Exception: mercury Lustrous Good conductors Malleable Ductile Nonmetals May be solid, liquid or gas Solids are brittle Nonconductors

23 Metalloids Have properties of metals and nonmetals

24 Group 1 Alkali Metals Most reactive metals Must be stored under oil Not found as free elements in nature Soft can be cut with a knife Reactions with water

25 Alkali Metals 1 valence electron Typically form +1 ions

26 Group 2 Alkaline Earth Metals

27 Group 2 Alkaline Earth Metals Less reactive than alkali metals

28 Group 2 Alkaline Earth Metals Less reactive than alkali metals Not found as free elements in nature

29 Group 2 Alkaline Earth Metals Less reactive than alkali metals Not found as free elements in Have 2 valence electrons

30 Group 2 Alkaline Earth Metals Less reactive than alkali metals Not found as free elements in nature Have 2 valence electrons Typically form +2 ions

31 Transition metals Groups 3-12

32 Transition metals Compounds of transition metals are often highly colored

33 Transition metals Many transition metals can form several cations Ex. Cr 6+, Cr 3+

34 Hemoglobin a metalloprotein! Deoxyhemoglobin (in veins) Oxyhemoglobin (near the heme) In arteries

35 Group 16 Chalcogens 6 valence electrons Tend to form -2 anions Aka oxygen family Periodic Videos: Selenium

36 Group 17 Halogens The most reactive nonmetals Periodic Videos: Fluorine

37 Group 17 Halogens The most reactive nonmetals 7 valence electrons Tend to form -1 anions

38 Group 17 Halogens The most reactive nonmetals 7 valence electrons Tend to form -1 anions Form diatomic molecules F 2, I 2, Cl 2, Br 2

39 Halogens

40 Group 18 Noble Gases Non-reactive gases Open University: Noble Gases 8 valence electrons Completely filled sublevels Don t tend to gain or lose electrons Basically don t form compounds

41 Group 18 Noble Gases Non-reactive gases 8 valence electrons Completely filled sublevels Don t tend to gain or lose electrons Basically don t form compounds

42 Organizing information By the mid-1800 s, about 70 elements were known

43 Organizing information By the mid-1800 s, about 70 elements were known Similarities of certain elements Coinage elements: copper, silver, gold

44 Organizing information By the mid-1800 s, about 70 elements were known Similarities of certain elements Coinage elements: copper, silver, gold Halogens ( salt-maker ): chlorine, bromine, iodine

45 Organizing information By the mid-1800 s, about 70 elements were known Similarities of certain elements Coinage elements: copper, silver, gold Halogens ( salt-maker ): chlorine, bromine, iodine Alkali metals: lithium, sodium, potassium

46 Early attempts at organizing Döbereiner s triads

47 Early attempts at organizing Döbereiner s triads Newland s Law of Octaves

48 Dmitri Mendeleev ( )

49 Dmitri Mendeleev ( ) 1869 published first periodic table of the elements

50 Dmitri Mendeleev ( ) 1869 published first periodic table of the elements Listed all known elements in order of increasing atomic mass

51 Dmitri Mendeleev ( ) 1869 published first periodic table of the elements Arranged rows so that elements with similar properties were side by side

52 Dmitri Mendeleev ( ) 1869 published first periodic table of the elements Arranged rows so that elements with similar properties were side by side (even if out of order by mass)

53 Dmitri Mendeleev ( ) Left blanks in table if no element with appropriate property was known

54 Dmitri Mendeleev ( ) Left blanks in table if no element with appropriate property was known This led to very accurate predictions of scandium, germanium and gallium

55 Henry Moseley ( ) Used x-ray diffraction data on the elements to determine the nuclear charge

56 Henry Moseley ( ) Used x-ray diffraction data on the elements to determine the nuclear charge Realized that the properties of the elements are related to atomic number

57 Henry Moseley ( ) Rearranged the periodic table based on atomic number

58 Glenn Seaborg Rearranged the periodic table by putting the lanthanides and actinides under the main body of the table Video

59 The Periodic Law When elements are arranged according to increasing atomic number, there is a regular and repeating pattern in their chemical and physical properties.

60 The Special 7 Elements that exist as diatomic molecules H 2 O 2 N 2 F 2 Cl 2 I 2 Br 2

61 The Special 7 Elements that exist as diatomic molecules H 2 O 2 N 2 F 2 Cl 2 I 2 Other elemental molecules: P 4 S 8 Br 2

62 Exceptional Electron Configurations Some elements have electron configurations that don t follow the arrowfilling diagram Ex. Cu Expected: Actual:

63 Exceptional Electron Configurations Some elements have electron configurations that don t follow the arrowfilling diagram Why? Special stability associated with half-filled or fully filled sublevels