GROUP VII The Halogens A guide for i GCSE students - PowerPoint PPT Presentation

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GROUP VII The Halogens A guide for i GCSE students

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  1. GROUP VII The Halogens A guide for iGCSE students 2010 SPECIFICATIONS KNOCKHARDY PUBLISHING

  2. GROUP VII INTRODUCTION This Powerpoint show is one of several produced to help students understand selected GCSE Chemistry topics. It is based on the requirements of the AQA 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 AS and A2 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. GROUP VII • CONTENTS • Introduction • Group trends • Group similarities • Reaction with metals • Displacement reactions • Summary • Quick quiz • Hydrogen chloride or hydrochloric acid?

  4. INTRODUCTION THE HALOGENS OCCUR IN GROUP VII OF THE PERIODIC TABLE 0 Group 1 2 3 4 5 6 7 F Cl Br I At

  5. INTRODUCTION THE HALOGENS OCCUR IN GROUP VII OF THE PERIODIC TABLE 0 Group 1 2 3 4 5 6 7 F Cl Br I At THEY ARE NON-METALS AND HAVE ELECTRONIC CONFIGURATIONS JUST ONE ELECTRON SHORT OF THE NEAREST NOBLE GAS

  6. GROUP PROPERTIES GENERAL• non-metals • exist as separate diatomic molecules… eg Cl2 • have seven electrons in their outer shells • form negative ions with a 1- charge • reaction with metals and halides

  7. GROUP PROPERTIES GENERAL • non-metals • exist as separate diatomic molecules… eg Cl2 • have seven electrons in their outer shells • form negative ions with a 1- charge • reaction with metals and halides TRENDS•appearance • boiling point • electronic configuration • atomic size • ionic size • reactivity

  8. GROUP TRENDS

  9. GROUP TRENDS APPEARANCE F2 Cl2 Br2 I2 Colour Yellow Green Red/brown Grey State (at RTP) GAS GAS LIQUID SOLID Vapour colour Yellow Green Red/brown Purple

  10. GROUP TRENDS APPEARANCE F2 Cl2 Br2 I2 Colour Yellow Green Red/brown Grey State (at RTP) GAS GAS LIQUID SOLID Vapour colour Yellow Green Red/brown Purple BOILING POINT F2 Cl2 Br2 I2 Boiling point / °C - 188 - 34 58 183 INCREASES down Group because more energy is required to separate the larger molecules.

  11. GROUP TRENDS ELECTRONIC CONFIGURATION F Cl Br I Atomic Number 9 17 35 53 Configuration 2,7 2,8,7 2,8,18,7 2,8,18,18,7 • electrons go into shells further from the nucleus

  12. GROUP TRENDS ATOMIC & IONIC RADIUS F Cl Br I Atomic radius / nm 0.064 0.099 0.111 0.128 NOT TO SCALE

  13. GROUP TRENDS ATOMIC & IONIC RADIUS F Cl Br I Atomic radius / nm 0.064 0.099 0.111 0.128 F¯ Cl¯ Br¯ I¯ Ionic radius / nm 0.136 0.181 0.195 0.216 ATOMIC RADIUS INCREASES down Group IONIC RADIUS INCREASES down Group • the greater the atomic number the more electrons there are these go into shells increasingly further from the nucleus • ions are larger than atoms - the added electron repels the others so radius gets larger

  14. GROUP SIMILARITIES

  15. GROUP SIMILARITIES ELECTRONIC CONFIGURATION F Cl Br I Atomic Number 9 17 35 53 Configuration 2,7 2,8,7 2,8,18,7 2,8,18,18,7 • all the atoms have seven electrons in their outer shell • ions are larger than atoms - the added electron repels the others so radius gets larger

  16. GROUP SIMILARITIES MOLECULAR FORMULA F Cl Br I Molecular formula F2 Cl2 Br2 I2 Bonding Covalent Covalent Covalent Covalent • all exist as diatomic molecules NOT TO SCALE

  17. GROUP SIMILARITIES ION FORMATION F Cl Br I Ion F¯ Cl¯ Br¯ I¯ Configuration 2,8 2,8,8 2,8,18,8 2,8,18,18,8 • all gain one electron to form a negative ion of charge 1- • ions are larger than atoms • the smaller the atom the easier it forms an ion

  18. GROUP SIMILARITIES ION FORMATION F Cl Br I Ion F¯ Cl¯ Br¯ I¯ Configuration 2,8 2,8,8 2,8,18,8 2,8,18,18,8 • all gain one electron to form a negative ion of charge 1- • ions are larger than atoms • the smaller the atom the easier it forms an ion REACTIVITY F Cl Br I Increasingly reactive Reactivity • reactivity decreases down the Group / increases up the Group

  19. REACTIONS OF HALOGENS 1. WITH METALS 2. WITH HALIDES

  20. REACTION OF HALOGENS WITH METALS

  21. REACTION OF HALOGENS WITH METALS HALOGENS REACT WITH METALS TO PRODUCE METAL HALIDES.

  22. REACTION OF HALOGENS WITH METALS HALOGENS REACT WITH METALS TO PRODUCE METAL HALIDES. THE EASE OF REACTION DECREASES DOWN THE GROUP F > Cl > Br > I

  23. REACTION OF HALOGENS WITH METALS HALOGENS REACT WITH METALS TO PRODUCE METAL HALIDES. THE EASE OF REACTION DECREASES DOWN THE GROUP F > Cl > Br > I THIS IS BECAUSE ‘THE LARGER THE HALOGEN ATOM, THE LESS EASILY IT ATTRACTS THE ELECTRON IT NEEDS TO FILL ITS OUTER SHELL’

  24. REACTION OF HALOGENS WITH METALS HALOGENS REACT WITH METALS TO PRODUCE METAL HALIDES. THE EASE OF REACTION DECREASES DOWN THE GROUP F > Cl > Br > I THIS IS BECAUSE ‘THE LARGER THE HALOGEN ATOM, THE LESS EASILY IT ATTRACTS THE ELECTRON IT NEEDS TO FILL ITS OUTER SHELL’ THE HALIDES OF GROUP I ARE… WHITE IONIC SOLIDS VERY SOLUBLE IN WATER SODIUM CHLORIDE (NaCl) IS A TYPICAL GROUP I HALIDE

  25. REACTION WITH ALKALI METALS

  26. REACTION WITH ALKALI METALS - Equations + SODIUM CHLORINE SODIUM CHLORIDE

  27. REACTION WITH ALKALI METALS - Equations Na + Cl2 NaCl SODIUM CHLORINE SODIUM CHLORIDE

  28. REACTION WITH ALKALI METALS - Equations Na + Cl2 NaCl SODIUM CHLORINE SODIUM CHLORIDE The equation doesn’t balance - multiply the formulae until it does

  29. REACTION WITH ALKALI METALS - Equations Na + Cl2 NaCl SODIUM CHLORINE SODIUM CHLORIDE 2Na + Cl2 2NaCl Balanced equation

  30. SODIUM CHLORIDE FORMATION Na Cl CHLORINE ATOM 2,8,7 SODIUM ATOM 2,8,1 11 protons; 11 electrons 17 protons; 17 electrons

  31. SODIUM CHLORIDE FORMATION + Na Cl CHLORIDE ION 2,8,8 SODIUM ION 2,8 11 protons; 10 electrons 17 protons; 18 electrons both species now have ‘full’ outer shells; ie they have the electronic configuration of a noble gas

  32. SODIUM CHLORIDE FORMATION + Na Cl CHLORIDE ION 2,8,8 SODIUM ION 2,8 Na Na+ + e¯ 2,8,1 2,8 ELECTRON TRANSFERRED Cl + e¯ Cl¯ 2,8,7 2,8,8

  33. DISPLACEMENT REACTIONS OF HALOGENS

  34. DISPLACEMENT REACTIONS OF HALOGENS HALOGENS GET LESS REACTIVE AS THE GROUP IS DESCENDED

  35. DISPLACEMENT REACTIONS OF HALOGENS HALOGENS GET LESS REACTIVE AS THE GROUP IS DESCENDED THIS DECREASE IN REACTIVITY DOWN THE GROUP CAN BE DEMONSTRATED USING DISPLACEMENT REACTIONS... A DISPLACEMENT REACTION IS WHERE ONE SPECIES TAKES THE PLACE OF ANOTHER IN A COMPOUND.

  36. DISPLACEMENT REACTIONS OF HALOGENS HALOGENS GET LESS REACTIVE AS THE GROUP IS DESCENDED THIS DECREASE IN REACTIVITY DOWN THE GROUP CAN BE DEMONSTRATED USING DISPLACEMENT REACTIONS... A DISPLACEMENT REACTION IS WHERE ONE SPECIES TAKES THE PLACE OF ANOTHER IN A COMPOUND. THE REACTIONS ARE EXAMPLES OF REDOX REACTIONS

  37. DISPLACEMENT REACTIONS OF HALOGENS CHLORINE WATER Pale green BROMINE WATER Orange SODIUM CHLORIDE SOLUTION Colourless SODIUM BROMIDE SOLUTION Colourless SODIUM IODIDE SOLUTION Colourless A SOLUTION OF THE HALOGEN IS ADDED TO A SOLUTION OF A HALIDE HALIDES ARE SALTS FORMED BETWEEN ELEMENTS AND HALOGENS

  38. DISPLACEMENT REACTIONS OF HALOGENS BROMINE WATER Orange SODIUM BROMIDE SOLUTION Colourless SODIUM IODIDE SOLUTION Colourless Experiment 1 CHLORINE WATER Pale green SODIUM CHLORIDE SOLUTION Colourless NO VISIBLE REACTION

  39. DISPLACEMENT REACTIONS OF HALOGENS BROMINE WATER Orange SODIUM CHLORIDE SOLUTION Colourless SODIUM IODIDE SOLUTION Colourless Experiment 2 CHLORINE WATER Pale green SODIUM BROMIDE SOLUTION Colourless BROMINE produced

  40. DISPLACEMENT REACTIONS OF HALOGENS BROMINE WATER Orange SODIUM CHLORIDE SOLUTION Colourless SODIUM BROMIDE SOLUTION Colourless Experiment 3 CHLORINE WATER Pale green SODIUM IODIDE SOLUTION Colourless IODINE produced

  41. DISPLACEMENT REACTIONS OF HALOGENS CHLORINE WATER Pale green SODIUM BROMIDE SOLUTION Colourless SODIUM IODIDE SOLUTION Colourless Experiment 4 BROMINE WATER Orange SODIUM CHLORIDE SOLUTION Colourless NO VISIBLE REACTION

  42. DISPLACEMENT REACTIONS OF HALOGENS CHLORINE WATER Pale green SODIUM CHLORIDE SOLUTION Colourless SODIUM IODIDE SOLUTION Colourless Experiment 5 BROMINE WATER Orange SODIUM BROMIDE SOLUTION Colourless NO VISIBLE REACTION

  43. DISPLACEMENT REACTIONS OF HALOGENS CHLORINE WATER Pale green SODIUM CHLORIDE SOLUTION Colourless SODIUM BROMIDE SOLUTION Colourless Experiment 6 BROMINE WATER Orange SODIUM IODIDE SOLUTION Colourless IODINE produced

  44. DISPLACEMENT REACTIONS OF HALOGENS SUMMARY OF OBSERVATIONS SODIUM CHLORIDE SODIUM BROMIDE SODIUM IODIDE CHLORINE Solution stays colourless NO REACTION 1 2 Solution goes from colourless to orange-yellow BROMINE FORMED 3 Solution goes from colourless to orange-red IODINE FORMED BROMINE Solution goes from colourless to orange-yellow NO REACTION 4 5 Solution goes from colourless to orange-yellow NO REACTION 6 Solution goes from colourless to red IODINE FORMED The colour change in Experiments 4 and 5 is due to dilution – there is no reaction

  45. DISPLACEMENT REACTIONS OF HALOGENS EQUATIONS CHLORINE + SODIUM BROMIDE CHLORINE + SODIUM IODIDE BROMINE + SODIUM IODIDE

  46. DISPLACEMENT REACTIONS OF HALOGENS EQUATIONS CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE

  47. DISPLACEMENT REACTIONS OF HALOGENS EQUATIONS CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE Cl2(aq) + NaBr(aq) —> Br2(aq) + NaCl(aq) The equation doesn’t balance - multiply the formulae until it does

  48. DISPLACEMENT REACTIONS OF HALOGENS EQUATIONS CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE Cl2(aq) + NaBr(aq) —> Br2(aq) + NaCl(aq) Cl2(aq) + 2NaBr(aq) —> Br2(aq) + 2NaCl(aq)

  49. DISPLACEMENT REACTIONS OF HALOGENS EQUATIONS CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE Cl2(aq) + 2NaBr(aq) —> Br2(aq) + 2NaCl(aq) IONIC EQUATION Cl2(aq) + 2Br¯(aq) —> Br2(aq) + 2Cl¯(aq)

  50. DISPLACEMENT REACTIONS OF HALOGENS EQUATIONS CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE Cl2(aq) + 2NaI(aq) —> I2(aq) + 2NaCl(aq) IONIC EQUATION Cl2(aq) + 2I¯(aq) —> I2(aq) + 2Cl¯(aq)