Teaching Tips for Lesson 8: Relating Electron

Transcription

1 Teaching Tips for Lesson 8: Relating Electron Arrangement to Reactivity Game Plan: A. Review orbital, electronic configuration notation and electron dot notation. B. Explore how elements form families on the periodic table. Read text together and discuss locations and names of the families of elements. C. Play Element Family Demo Derby! D. Assign Lesson 8 practice pages. E. Give Lesson 8 Test. A. Review orbital, electronic configuration notation and electron dot notation. Take plenty of time at the beginning of class this week to review orbital notation, electronic configuration notation and electron dot notation. Review how these notations help chemists describe the location of electrons within atoms of particular elements. Consider playing a few rounds of the Teamwork game to get your students thinking about these notations once again. B. Exploration of families of the periodic table. Continue class by beginning to explore how the arrangements of electrons have direct relationships to how the elements are arranged into families on the periodic table. Read through the text with your students and follow the exercises presented Your students should readily begin to see the trends of these relationships. Emphasize that just as members of your students families have similarities, so do members of each family of elements. 121 Copyright 2010, Hideaway Ventures

2 C. Play Element Family Demo Derby A large empty play area such as a gym works well for this game or you can move your student desks along the walls of your classroom to make an open play area. Have your students assemble in a group in the center of the play area. On five chairs place signs designating the five families of elements presented in this lesson. Signs for the chairs are found on the next page. Position yourself so that your students can readily hear your voice. Instruct your students to choose a partner and to link elbows. One student in each pair should hold a periodic table. Play begins by you calling out the name of an element found in one of the element families. As pairs, the students must find the element on their periodic table and then dash to the appropriate chair. For example, if you called the element chlorine, all pairs of students should find chlorine on their periodic tables and accordingly dash to the chair with the halogen label. The object of the game is to not be the last pair to the chair! Once all students find the appropriate chair, have them return to the center of playing area. Call another element and play continues. We encourage you to NOT eliminate the slowest pair. Instead, continue play promoting a fun, jolly atmosphere. At the end of playing time, reward all players with hearty round of applause! A variation of this game, that we strongly encourage you to play, is instead of calling out a particular element name, call out the number of valence electrons (dots) found in the various families of elements being studied. Begin play by telling your students that now instead of an element name, that you are going to call out the number valence electrons that the element families share. The student pairs are to dash to the appropriate element family chair. For example, if you call out the number 2 (indicating elements with two valence electrons), the student pairs should run to the calcium family chair. D. Assign Lesson 9 practice pages. E. Give Lesson 9 Test. Note for this test that you should make copies of the periodic table of elements found on page 125 of this lesson. This table only has the element symbols and atomic numbers present. 122

3 Noble Gas Family Sodium Family Calcium Family Oxygen Family Halogen Family 123

4 NAME DATE FRIENDLY CHEMISTRY Lesson 8 Test Relating Electron Arrangement to Families on the Periodic Table Listed below are ten elements. For each element, tell the number of valence electrons, write the electron dot notation and finally, the name of the family to which it belongs. Element Name Number of Valence Electrons Dot Notation Member of the family. 1. Lithium 2. Oxygen 3. Barium 4. Argon 5. Magnesium 6. Rubidium 7. Calcium 8. Fluorine 9. Sodium 10. Bromine 124

5 125 Friendly Chemistry 1 H 2 He 3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 10 Ne 11 Na 12 Mg 13 Al 14 Si 15 P 16 S 17 Cl 18 Ar 19 K 20 Ca 21 Sc 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 28 Ni 29 Cu 30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 36 Kr 37 Rb 38 Sr 39 Y 40 Zr 41 Nb 42 Mo 43 Tc ) 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 49 In 50 Sn 51 Sb 52 Te 53 I 54 Xe 55 Cs 56 Ba 71 Lu 72 Hf 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 Hg 81 Tl 82 Pb 83 Bi 84 Po 85 At 86 Rn 87 Fr 88 Ra 103 Lr 104 Unq 105 Unp 106 Unh 107 Uns 108 Uno 109 Une Periodic Table Of the Elements

6 126

7 Lesson 8: Relating Electron Arrangement to Reactivity In Lessons 5, 6 and 7 we discussed how to take the information from your Doo- Wop Board and, using the quantum mechanics code, describe the arrangement of electrons in an atom with orbital, electron configuration and electron dot notations. In this lesson we will take those descriptive notations and relate them to the reactivity, or lack of reactivity, of various elements in the periodic table. In addition, we will look at other properties of elements and begin to describe why the elements are arranged as they are in the periodic table. Let s begin by examining the electron dot notations of a particular set of elements. Using the information presented in the last lessons, write the electron dot notations for the following elements. Remember to write the electron configuration notation first and then represent the valence electrons (those electrons in the outermost energy level or orbit) as dots. 127 S69

8 Hydrogen Lithium Sodium Potassium Rubidium S70 128

9 Did you notice anything in particular after completing the electron dot notations for these five elements? Yes, each of these elements has one valence electron. Now, find these elements on your periodic table of elements. Did you find something else that these elements hold in common? Yes, these elements are found in the farthest left column of the periodic table of elements. Columns of elements on the periodic table are known as families or groups. 1 H Hydrogen Li Lithium Be Beryllium Families of elements are found in columns on the periodic table. 11 Na Sodium K Potassium Mg Magnesium Ca Calcium Sc Scandium Ti Titanium V Vanadium Rb Rubidium Sr Strontium Y Yttrium Zr Zirconium Nb Niobium Cs Cesium Ba Barium Lu Lutetium Hf Hafnium Ta Tantalum Fr Francium (223) 88 Ra Radium (226) 103 Lr Lawrencium (256) 104 Unq 105 Unp 129 S71

10 The term family is more descriptive in that, possibly like your family, its members generally resemble each other. In other words, if you have biological brothers or sisters, you can usually see similarities in hair color, facial features or body build among you and your brothers or sisters. In an analogous way, the elements which are within the same column on the periodic table of elements, have similar features or properties and are known as families of elements. Just as your family has a last name, the families on the periodic table of elements have names. The family of elements you just examined is known as the sodium family (that is, hydrogen, lithium, sodium, potassium, rubidium, cesium and francium are members of the sodium family). 1 H Hydrogen Li Lithium Be Beryllium The Sodium Family members here are shaded in gray. 11 Na Sodium K Potassium Mg Magnesium Ca Calcium Sc Scandium Ti Titanium V Vanadium Rb Rubidium Sr Strontium Y Yttrium Zr Zirconium Nb Niobium Cs Cesium Ba Barium Lu Lutetium Hf Hafnium Ta Tantalum Fr Francium (223) 88 Ra Radium (226) 103 Lr Lawrencium (256) 104 Unq 105 Unp S72 130

11 Let s look at another family of elements. Write the electron dot notations for the following elements. Neon Argon Krypton Electron configuration Atomic notation: Mass Again, can you see what feature is common to this set of elements? Yes, each of the elements in this family of elements has eight valence electrons. Look at your periodic table to find these elements. Do you see them on the far right side of your periodic table? This family of elements is known as the noble gas family or inert gas family. Note that helium is also a member of this family of elements. If you write the electron dot notation for helium, you will find that helium has only two valence electrons and not eight like the other members in the family. Later in this chapter we will discuss why helium is included in the noble gas family. 131 S73

12 2 He Helium B Boron C Carbon N Nitrogen O Oxygen F Fluorine Ne Neon Al Aluminum Si Silicon P Phosphorus S Sulfur Cl Chlorine Ar Argon Zn Zinc Cd Cadmium Ga Gallium In Indium Ge Germanium Sn Tin As Arsenic Sb Antimony Se Selenium Te Tellurium Br Bromine I Iodine Kr Krypton Xe Xenon The Noble Gas Family members are shaded in gray. 80 Hg Mercury Tl Thallium Pb Lead Bi Bismuth Po Polonium (210) 85 At Astatine (210) 86 Rn Radon (222) Another family to be introduced at this point consists of the following elements. Write the electron dot notation for these elements and then find them on your periodic table. Fluorine Chlorine Bromine S74 132

13 How many valence electrons do each of these elements have? If you said seven, you are correct! This family of elements can be found just to the left of the noble gas family. The name of this family of elements is the halogens. Notice that each family member s name ends in -ine (fluorine, chlorine, bromine, iodine and astatine). 5 B Boron The Halogen Family members are shaded in gray. 6 C Carbon N Nitrogen O Oxygen F Fluorine He Helium Ne Neon Co Cobalt Ni Nickel Cu Copper Zn Zinc Al Aluminum Ga Gallium Si Silicon Ge Germanium P Phosphorus As Arsenic S Sulfur Se Selenium Cl Chlorine Br Bromine Ar Argon Kr Krypton Rh Rhodium Pd Palladium Ag Silver Cd Cadmium In Indium Sn Tin Sb Antimony Te Tellurium I Iodine Xe Xenon Ir Iridium Pt Platinum Au Gold Hg Mercury Tl Thallium Pb Lead Bi Bismuth Po Polonium (210) 85 At Astatine (210) 86 Rn Radon (222) 109 Une Let s continue by examining another family of elements. Write the electron dot notations for each of the elements listed below and then find them on your periodic table. Oxygen Electron dot notation 133 S75

14 Sulfur Selenium How many valence electrons do each of these elements have? If you said six, you re right! Look at the periodic table below to see where this family of elements resides. The name of this family of elements is the oxygen family. The members of the oxygen family share properties unique to that family. 5 B Boron Al Aluminum Ga Gallium In Indium Tl Thallium The Oxygen Family members are shaded in gray. 6 C Carbon Si Silicon Ge Germanium Sn Tin Pb Lead N Nitrogen P Phosphorus As Arsenic Sb Antimony Bi Bismuth O Oxygen S Sulfur Se Selenium Te Tellurium Po Polonium (210) 9 F Fluorine Cl Chlorine Br Bromine I Iodine At Astatine (210) 2 He Helium Ne Neon Ar Argon Kr Krypton Xe Xenon Rn Radon (222) S76 134

15 One additional family that we will examine consists of the following elements. Write the electron dot notation for each of the elements below and then find them on your periodic table of elements. Beryllium Magnesium Calcium 1 H Hydrogen Strontium 3 Li Lithium Be Beryllium Did you find this set of elements next door to the sodium family? This set of elements, with two valence electrons each, is known as the calcium family. 11 Na Sodium K Potassium Rb Rubidium Mg Magnesium Ca Calcium Sr Strontium Sc Scandium Y Yttrium The Calcium Family members are shaded in gray. 55 Cs Cesium Fr Francium (223) 56 Ba Barium Ra Radium (226) 71 Lu Lutetium Lr Lawrencium (256) 135 S77

16 Sodium Family (1 dot) 1 H Hydrogen Li Lithium Na Sodium K Potassium Rb Rubidium Cs Cesium Fr Francium (223) Calcium Family (2 dots) Oxygen Family (6 dots) 4 Be Beryllium Mg Magnesium Ca Calcium Sr Strontium Ba Barium Ra Radium (226) 21 Sc Scandium Y Yttrium Lu Lutetium Lr Lawrencium (256) 22 Ti Titanium Zr Zirconium Hf Hafnium Unq 23 V Vanadium Nb Niobium Ta Tantalum Unp 24 Cr Chromium Mo Molybdenum W Tungsten Unh 25 Mn Manganese Tc Technetium (99) 75 Re Rhenium Uns 26 Fe Iron Ru Ruthenium Os Osmium Uno 27 Co Cobalt Rh Rhodium Ir Iridium Une 28 Ni Nickel Pd Palladium Pt Platinum Cu Copper Ag Silver Au Gold Zn Zinc Cd Cadmium Hg Mercury B Boron Al Aluminum Ga Gallium In Indium Tl Thallium Noble Gas Family (8 dots) Halogen Family (7 dots) 6 C Carbon Si Silicon Ge Germanium Sn Tin Pb Lead N Nitrogen P Phosphorus As Arsenic Sb Antimony Bi Bismuth O Oxygen S Sulfur Se Selenium Te Tellurium Po Polonium (210) 9 F Fluorine Cl Chlorine Br Bromine I Iodine At Astatine (210) 2 He Helium Ne Neon Ar Argon Kr Krypton Xe Xenon Rn Radon (222) Friendly Chemistry Review the periodic table of elements below to see the five families we have discussed so far. Take a moment to label these element families on your own periodic table of elements. Then, practice learning the family names by playing Element Family Demo Derby! S78 136

17 Name Date Friendly Chemistry Element Family Practice 1 Write the dot notation and then tell the family to which the elements listed below belong. Element Name Electron Dot Notation Element Family 1. Sodium 2. Oxygen 3. Helium 4. Potassium 5. Fluorine 6. Calcium 7. Beryllium 8. Hydrogen 9. Argon 10. Sulfur 11. Strontium 12. Chlorine 13. Magnesium 14. Iodine 15. Lithium 16. Astatine 17. Barium 18. Krypton 19. Xenon 20. Rubidium 137 S79

18 Name Date Friendly Chemistry Element Family Practice 2 Write the dot notation and then tell the family to which the elements listed below belong. Element Name Electron Dot Notation Element Family 1. Silicon 2. Helium 3. Sulfur 4. Argon 5. Calcium 6. Beryllium 7. Fluorine 8. Neon 9. Krypton 10. Bromine 11. Hydrogen 12. Potassium 13. Lithium 14. Oxygen 15. Selenium 16. Strontium 17. Iodine 18. Xenon 19. Cesium S Enough practice for one day! This one s a free one! 138 We ll just call it an early Christmas present!