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GROUP 1 The alkali metals National 5 Chemistry KNOCKHARDY PUBLISHING.

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Presentation on theme: "GROUP 1 The alkali metals National 5 Chemistry KNOCKHARDY PUBLISHING."— Presentation transcript:

1 GROUP 1 The alkali metals National 5 Chemistry KNOCKHARDY PUBLISHING

2 GROUP I INTRODUCTION This Powerpoint show is one of several produced to help students understand selected National 5 Chemistry topics. It is based on the requirements of the SQA specification but is suitable for other examination boards. Individual students may use the material at home for revision purposes and it can also prove useful for classroom teaching with an interactive white board. Additional Powerpoints, and the full range of Chemistry topics, are available from the KNOCKHARDY WEBSITE at... www.knockhardy.org.uk All diagrams and animations in this Powerpoint are original and created by Jonathan Hopton. Permission must be obtained for their use in any commercial work.

3 CONTENTS CONTENTS Introduction Group trends Group similarities Flame tests Reaction with water Reaction with halogens Summary Quick quiz GROUP I

4 INTRODUCTION

5 INTRODUCTION THE ALKALI METALS ARE IN GROUP I OF THE PERIODIC TABLE Group 1 2 3 4 5 6 7 0 Li Na K Rb Fr Cs

6 INTRODUCTION THE ALKALI METALS ARE IN GROUP I OF THE PERIODIC TABLE Group 1 2 3 4 5 6 7 0 Li Na K Rb Fr THEY ARE VERY REACTIVE METALS AND HAVE ELECTRONIC CONFIGURATIONS WITH ONE ELECTRON IN THE OUTER SHELL Cs

7 GROUP PROPERTIES GENERAL metals exist as separate diatomic molecules… eg C l 2 have one electron in their outer shell form positive ions with a 1+ charge vigorous reaction with water and halides

8 GROUP PROPERTIES GENERAL metals exist as separate diatomic molecules… eg C l 2 have one electron in their outer shell form positive ions with a 1+ charge vigorous reaction with water and halides TRENDS melting point hardness electronic configuration atomic size ionic size reactivity

9 GROUP TRENDS

10 APPEARANCE Density / gcm -3 LiNaKRb 0.530.970.861.53 Cs 1.87 AppearanceGrey solid Flame testCrimson YellowLilacRed-violetBlue-violet

11 GROUP TRENDS DECREASES down Group as the atoms get larger APPEARANCE MELTING POINT Melting point / ° C LiNaKRb 180.79863.839.2 Cs 43.2 Density / gcm -3 LiNaKRb 0.530.970.861.53 Cs 1.87 AppearanceGrey solid Flame testCrimson YellowLilacRed-violetBlue-violet

12 GROUP TRENDS Configuration ELECTRONIC CONFIGURATION Atomic Number LiNaKRb 3111937 Cs 55 2,12,8,12,8,8,12,8,18,8,12,8,18,18,8,1

13 GROUP TRENDS electrons go into shells further from the nucleus Configuration ELECTRONIC CONFIGURATION Atomic Number LiNaKRb 3111937 Cs 55 2,12,8,12,8,8,12,8,18,8,12,8,18,18,8,1 11+ 3+ 19+ LITHIUM 2,1 SODIUM 2,8,1 POTASSIUM 2,8,8,1

14 GROUP TRENDS LiNaKRb ATOMIC RADIUS 0.1520.1850.2270.247Atomic radius / nm Cs 0.265 Li Rb Na K Cs

15 GROUP TRENDS ATOMIC RADIUSINCREASES down Group the greater the atomic number the more electrons there are; these go into shells increasingly further from the nucleus LiNaKRb ATOMIC RADIUS 0.1520.1850.2270.247Atomic radius / nm Cs 0.265 Li Rb Na K Cs

16 GROUP TRENDS ATOMIC & IONIC RADIUS LiNaKRb 0.1520.1850.2270.247Atomic radius / nm Cs 0.265 Li Rb Na K Cs Li + Na + K+K+ Rb + 0.0680.0980.1330.148Ionic radius / nm Cs+ 0.167 Li + Rb + Na + K+K+ Cs + IONIC RADIUS INCREASES down Group ions are smaller than atoms - the removal of an electron means that there are now fewer shells

17 GROUP SIMILARITIES

18 ION FORMATION Configuration Ion LiNaKRb Li + Na + K+K+ Rb + Cs Cs + 22,82,8,82,8,18,82,8,18,18,8

19 GROUP SIMILARITIES ION FORMATION atoms ‘lose’ one electron to form a positive ion of charge 1+ ions are smaller than atoms the larger the atom the easier it forms an ion because the electron being removed is further from the nucleus Configuration Ion LiNaKRb Li + Na + K+K+ Rb + Cs Cs + 22,82,8,82,8,18,82,8,18,18,8

20 GROUP SIMILARITIES ION FORMATION atoms ‘lose’ one electron to form a positive ion of charge 1+ ions are smaller than atoms the larger the atom the easier it forms an ion because the electron being removed is further from the nucleus Configuration Ion LiNaKRb Li + Na + K+K+ Rb + Cs Cs + 22,82,8,82,8,18,82,8,18,18,8 11+ SODIUM ATOM 11 PROTONS 11 ELECTRONS SODIUM ION 11 PROTONS 10 ELECTRONS

21 GROUP SIMILARITIES ION FORMATION atoms ‘lose’ one electron to form a positive ion of charge 1+ ions are smaller than atoms the larger the atom the easier it forms an ion because the electron being removed is further from the nucleus reactivity increases down the Group as atoms get larger Increasingly reactive Configuration Ion LiNaKRb Li + Na + K+K+ Rb + Cs Cs + 22,82,8,82,8,18,82,8,18,18,8 LiNaKRbCs REACTIVITY

22 FLAME TESTS

23 SOME METALS CAN BE IDENTIFIED BY FLAME TESTS A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT

24 FLAME TESTS SOME METALS CAN BE IDENTIFIED BY FLAME TESTS A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT Cu Na Ba K Ca NORMAL BUNSEN BLUE- BRIGHT APPLE LILAC BRICK GREEN YELLOW GREEN RED

25 FLAME TESTS SOME METALS CAN BE IDENTIFIED BY FLAME TESTS A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT A LINE SPECTRUM IS PRODUCED

26 FLAME TESTS CONTINUOUS SPECTRUM A LINE SPECTRUM IS PRODUCED SOME METALS CAN BE IDENTIFIED BY FLAME TESTS A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT

27 FLAME TESTS CONTINUOUS SPECTRUM LINE SPECTRUM A LINE SPECTRUM IS PRODUCED SOME METALS CAN BE IDENTIFIED BY FLAME TESTS A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT

28 FLAME TESTS CONTINUOUS SPECTRUM LINE SPECTRUM EACH METAL HAS ITS OWN CHARACTERISTIC LINE SPECTRUM A LINE SPECTRUM IS PRODUCED SOME METALS CAN BE IDENTIFIED BY FLAME TESTS A SAMPLE OF ONE OF THEIR SALTS IS PLACED IN A BUNSEN FLAME THE HEAT OF THE FLAME GIVES ELECTRONS ENERGY THE ELECTRONS THEN GIVE OUT ENERGY AS LIGHT

29 REACTIONS OF ALKALI METALS

30 REACTIVITY INCREASES DOWN THE GROUP The further the outer shell electron is from the nucleus, the easier it is to remove and the easier it becomes to form a positive ion. Because of this, alkali metals get more reactive as you go down the group. REACTIONS OF ALKALI METALS

31 REACTIVITY INCREASES DOWN THE GROUP The further the outer shell electron is from the nucleus, the easier it is to remove and the easier it becomes to form a positive ion. Because of this, alkali metals get more reactive as you go down the group. LITHIUM 2,1 11+ 3+ SODIUM 2,8,1 19+ POTASSIUM 2,8,8,1 REACTIONS OF ALKALI METALS GETS INCREASINGLY EASIER TO REMOVE THE OUTER SHELL ELECTRON

32 REACTION WITH WATER

33 1.GROUP I METALS REACT WITH COLD WATER 2.THE REACTIVITY INCREASES DOWN THE GROUP 3.HYDROGEN GAS IS PRODUCED 4.A METAL HYDROXIDE IS FORMED 5.GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS 6.THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS

34 REACTION WITH WATER 1.GROUP I METALS REACT WITH COLD WATER 2.THE REACTIVITY INCREASES DOWN THE GROUP 3.HYDROGEN GAS IS PRODUCED 4.A METAL HYDROXIDE IS FORMED 5.GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS 6.THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS LITHIUM FLOATS STEADILY GIVES OFF A GAS CLEAR ALKALINE SOLUTION LEFT LITHIUM HYDROXIDE FORMED

35 REACTION WITH WATER 1.GROUP I METALS REACT WITH COLD WATER 2.THE REACTIVITY INCREASES DOWN THE GROUP 3.HYDROGEN GAS IS PRODUCED 4.A METAL HYDROXIDE IS FORMED 5.GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS 6.THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS SODIUM FLOATS AND MOVES ABOUT MELTS TO A SPHERE GIVES OFF A GAS YELLOW FLAME CLEAR ALKALINE SOLUTION LEFT SODIUM HYDROXIDE FORMED ANIMATION

36 REACTION WITH WATER 1.GROUP I METALS REACT WITH COLD WATER 2.THE REACTIVITY INCREASES DOWN THE GROUP 3.HYDROGEN GAS IS PRODUCED 4.A METAL HYDROXIDE IS FORMED 5.GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS 6.THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS POTASSIUM FLOATS AND MOVES ABOUT VIGOROUS REACTION GIVES OFF A GAS LILAC FLAME CLEAR ALKALINE SOLUTION LEFT POTASSIUM HYDROXIDE FORMED ANIMATION

37 REACTION WITH WATER 1.GROUP I METALS REACT WITH COLD WATER 2.THE REACTIVITY INCREASES DOWN THE GROUP 3.HYDROGEN GAS IS PRODUCED 4.A METAL HYDROXIDE IS FORMED 5.GROUP I HYDROXIDES ARE WHITE CRYSTALLINE SOLIDS 6.THE HYDROXIDES DISSOLVE IN WATER TO GIVE ALKALINE SOLUTIONS RUBIDIUM WHAT WOULD YOU EXPECT?

38 REACTION WITH WATER- Equations SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN Write out the word equation

39 Na + H 2 O NaOH + H 2 SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN Write out the word equation Write out the formulae REACTION WITH WATER- Equations

40 Na + H 2 O NaOH + H 2 SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN Write out the word equation Write out the formulae If the equation doesn’t balance, multiply the formulae until it does REACTION WITH WATER- Equations

41 Na + H 2 O NaOH + H 2 SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN Write out the word equation Write out the formulae Na + 2H 2 O NaOH + H 2 If the equation doesn’t balance, multiply the formulae until it does REACTION WITH WATER- Equations

42 Na + H 2 O NaOH + H 2 SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN Write out the word equation Na + 2H 2 O 2NaOH + H 2 Write out the formulae Na + 2H 2 O NaOH + H 2 If the equation doesn’t balance, multiply the formulae until it does REACTION WITH WATER- Equations

43 Na + H 2 O NaOH + H 2 SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN Write out the word equation Na + 2H 2 O 2NaOH + H 2 Write out the formulae Na + 2H 2 O NaOH + H 2 If the equation doesn’t balance, multiply the formulae until it does 2Na + 2H 2 O 2NaOH + H 2 The equation is balanced. REACTION WITH WATER- Equations

44 LITHIUM + WATER LITHIUM HYDROXIDE + HYDROGEN 2Li + 2H 2 O 2LiOH + H 2 REACTION WITH WATER- Equations

45 2Li + 2H 2 O 2LiOH + H 2 2Na + 2H 2 O 2NaOH + H 2 LITHIUM + WATER LITHIUM HYDROXIDE + HYDROGEN SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN REACTION WITH WATER- Equations

46 2Li + 2H 2 O 2LiOH + H 2 2Na + 2H 2 O 2NaOH + H 2 POTASSIUM + WATER RUBIDIUM + WATER LITHIUM + WATER LITHIUM HYDROXIDE + HYDROGEN SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN REACTION WITH WATER- Equations

47 2Li + 2H 2 O 2LiOH + H 2 2Na + 2H 2 O 2NaOH + H 2 POTASSIUM + WATER POTASSIUM HYDROXIDE + HYDROGEN 2K + 2H 2 O 2KOH + H 2 RUBIDIUM + WATER RUBIDIUM HYDROXIDE + HYDROGEN 2Rb + 2H 2 O 2RbOH + H 2 LITHIUM + WATER LITHIUM HYDROXIDE + HYDROGEN SODIUM + WATER SODIUM HYDROXIDE + HYDROGEN REACTION WITH WATER- Equations

48 REACTION WITH HALOGENS

49 ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES.

50 REACTION WITH HALOGENS ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES. SODIUM CHLORINE SODIUM CHLORIDE +

51 REACTION WITH HALOGENS ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES. SODIUM CHLORINE SODIUM CHLORIDE + POTASSIUM CHLORINE +

52 REACTION WITH HALOGENS ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES. SODIUM CHLORINE SODIUM CHLORIDE + POTASSIUM CHLORINE POTASSIUM CHLORIDE +

53 REACTION WITH HALOGENS ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES. SODIUM CHLORINE SODIUM CHLORIDE + POTASSIUM CHLORINE POTASSIUM CHLORIDE + SODIUM BROMINE +

54 REACTION WITH HALOGENS ALKALI METALS REACT VIGOROUSLY WITH HALOGENS TO FORM IONIC COMPOUNDS CALLED HALIDES. SODIUM CHLORINE SODIUM CHLORIDE + POTASSIUM CHLORINE POTASSIUM CHLORIDE + SODIUM BROMINE SODIUM BROMIDE +

55 REACTION WITH HALOGENS - Equations Na + Cl 2 NaC l SODIUM CHLORINE SODIUM CHLORIDE

56 REACTION WITH HALOGENS - Equations Na + Cl 2 NaC l The equation doesn’t balance - multiply the formulae until it does SODIUM CHLORINE SODIUM CHLORIDE

57 REACTION WITH HALOGENS- Equations 2Na + C l 2 2NaC l Na + C l 2 NaC l SODIUM CHLORINE SODIUM CHLORIDE The equation is balanced

58 ClCl SODIUM ATOM 2,8,1 Na CHLORINE ATOM 2,8,7 11 protons; 11 electrons17 protons; 17 electrons FORMATION OF SODIUM CHLORIDE PRESS THE SPACE BAR TO START THE ANIMATION

59 ClCl SODIUM ION 2,8 Na CHLORIDE ION 2,8,8 both species now have ‘full’ outer shells; ie they have the electronic configuration of a noble gas + 11 protons; 10 electrons17 protons; 18 electrons FORMATION OF SODIUM CHLORIDE

60 ClCl SODIUM ION 2,8 Na CHLORIDE ION 2,8,8 NaNa + + e¯ 2,8,1 2,8 ELECTRON TRANSFERRED C l + e¯ C l ¯ 2,8,7 2,8,8 + FORMATION OF SODIUM CHLORIDE

61 SYMBOL ELECTRONIC CONFIGURATION HARDNESS DENSITY (Compared to water) Li CAN BE CUT JUST OVER HALF POTASSIUM Na ● ● LITHIUMSODIUM K METHOD OF STORAGE MELTING POINT IN OIL 181 °C IN OIL 91 °C IN OIL 63 °C JUST LIGHTER A BIT LIGHTER REACTION WITH OXYGEN IN THE AIR Tarnishes quickly Tarnishes very quickly REACTION WITH WATER steady fast very fast FORMULA OF OXIDE Li 2 0 Na 2 OK2OK2O PRODUCTS LITHIUM HYDROXIDE & HYDROGEN SODIUM HYDROXIDE & HYDROGEN POTASSIUM HYDROXIDE & HYDROGEN EASY TO CUTVERY EASY TO CUT 2,12,8,1 2,8,8,1 GROUP I - SUMMARY

62 QUICK QUIZ 1.ELEMENTS IN GROUP I ARE KNOWN AS THE ………. METALS 2.WHAT ARE THE NAMES OF THE ELEMENTS? 3.HOW DOES THE ATOMIC NUMBER CHANGE DOWN THE GROUP? 4.HOW DOES THE MELTING POINT CHANGE? 5.HOW DOES THE ATOMIC SIZE (RADIUS) CHANGE? 6.HOW MANY ELECTRONS DO THEY HAVE IN THE OUTER SHELL? 7.WHAT TYPE OF ION DO THEY FORM? 8.HOW DOES THEIR REACTIVITY CHANGE DOWN THE GROUP? 9.WHAT TYPE OF COMPOUND DO THEY FORM WITH NON-METALS? 10.DO THEIR HYDROXIDES DISSOLVE IN WATER? 11.WHAT TYPE OF SOLUTION DO THEIR HYDROXIDES GIVE? 12.HOW CAN YOU EXPLAIN THEIR RELATIVE REACTIVITY IN TERMS OF THE ATOMIC STRUCTURE?

63 QUICK QUIZ - ANSWERS 1.ALKALI METALS 2.LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, FRANCIUM 3.ATOMIC NUMBER INCREASES DOWN THE GROUP 4.MELTING POINT DECREASES DOWN THE GROUP 5.ATOMIC SIZE INCREASES DOWN THE GROUP 6.ALL HAVE ONE ELECTRON IN THE OUTER SHELL (ENERGY LEVEL) 7.FORM IONS OF CHARGE +1 8.REACTIVITY INCREASES DOWN THE GROUP 9.FORM IONIC COMPOUNDS WITH NON-METALS 10.HYDROXIDES DISSOLVE IN WATER 11.HYDROXIDES FORM ALKALINE SOLUTIONS 12.AS THE ATOMS GET BIGGER THE OUTER SHELL ELECTRON IS FURTHER FROM THE NUCLEUS SO IS EASIER TO REMOVE; THE METALS BECOME MORE REACTIVE

64 GROUP 1 The alkali metals THE END © 2011 KNOCKHARDY PUBLISHING & JONATHAN HOPTON


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