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KNOCKHARDY PUBLISHING
GROUP VII The Halogens National 5 Chemistry KNOCKHARDY PUBLISHING
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GROUP VII www.knockhardy.org.uk 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... 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.
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GROUP VII CONTENTS Introduction Group trends Group similarities
Reaction with metals Displacement reactions Summary Quick quiz
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THE HALOGENS OCCUR IN GROUP VII OF THE PERIODIC TABLE
INTRODUCTION THE HALOGENS OCCUR IN GROUP VII OF THE PERIODIC TABLE Group F Cl Br I At
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THE HALOGENS OCCUR IN GROUP VII OF THE PERIODIC TABLE
INTRODUCTION THE HALOGENS OCCUR IN GROUP VII OF THE PERIODIC TABLE Group F Cl Br I At THEY ARE NON-METALS AND HAVE ELECTRONIC CONFIGURATIONS JUST ONE ELECTRON SHORT OF THE NEAREST NOBLE GAS
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GROUP PROPERTIES • exist as separate diatomic molecules… eg Cl2
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
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GROUP PROPERTIES • exist as separate diatomic molecules… eg Cl2
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
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GROUP TRENDS
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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
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GROUP TRENDS APPEARANCE BOILING POINT
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.
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ELECTRONIC CONFIGURATION
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
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GROUP TRENDS ATOMIC & IONIC RADIUS F Cl Br I Atomic radius / nm 0.064
0.099 0.111 0.128 NOT TO SCALE
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GROUP TRENDS ATOMIC & IONIC RADIUS ATOMIC RADIUS INCREASES down Group
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
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GROUP SIMILARITIES
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ELECTRONIC CONFIGURATION
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
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GROUP SIMILARITIES MOLECULAR FORMULA • all exist as diatomic molecules
Cl Br I Molecular formula F2 Cl2 Br2 I2 Bonding Covalent Covalent Covalent Covalent • all exist as diatomic molecules NOT TO SCALE
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GROUP SIMILARITIES ION FORMATION
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
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Increasingly reactive
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 Reactivity Increasingly reactive • reactivity decreases down the Group / increases up the Group
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REACTIONS OF HALOGENS 1. WITH METALS 2. WITH HALIDES
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REACTION OF HALOGENS WITH METALS
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REACTION OF HALOGENS WITH METALS
HALOGENS REACT WITH METALS TO PRODUCE METAL HALIDES.
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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
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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’
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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
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REACTION WITH ALKALI METALS
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REACTION WITH ALKALI METALS - Equations
SODIUM CHLORINE SODIUM CHLORIDE +
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REACTION WITH ALKALI METALS - Equations
Na Cl NaCl SODIUM CHLORINE SODIUM CHLORIDE
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REACTION WITH ALKALI METALS - Equations
Na Cl NaCl SODIUM CHLORINE SODIUM CHLORIDE The equation doesn’t balance - multiply the formulae until it does
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REACTION WITH ALKALI METALS - Equations
Na Cl NaCl SODIUM CHLORINE SODIUM CHLORIDE 2Na Cl NaCl Balanced equation
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SODIUM CHLORIDE FORMATION
Na Cl SODIUM ATOM 2,8,1 CHLORINE ATOM 2,8,7 11 protons; 11 electrons 17 protons; 17 electrons
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SODIUM CHLORIDE FORMATION
+ Na Cl SODIUM ION 2,8 CHLORIDE ION 2,8,8 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
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SODIUM CHLORIDE FORMATION
+ Na Cl SODIUM ION 2,8 CHLORIDE ION 2,8,8 Na Na e¯ 2,8, ,8 ELECTRON TRANSFERRED Cl e¯ Cl¯ 2,8, ,8,8
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DISPLACEMENT REACTIONS OF HALOGENS
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DISPLACEMENT REACTIONS OF HALOGENS
HALOGENS GET LESS REACTIVE AS THE GROUP IS DESCENDED
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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.
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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
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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
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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
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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
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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
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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
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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
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DISPLACEMENT REACTIONS OF HALOGENS
SUMMARY OF OBSERVATIONS SODIUM CHLORIDE SODIUM BROMIDE SODIUM IODIDE CHLORINE 1 Solution stays colourless NO REACTION Solution goes from colourless to orange-yellow BROMINE FORMED 2 3 Solution goes from colourless to orange-red IODINE FORMED BROMINE 4 Solution goes from colourless to orange-yellow NO REACTION Solution goes from colourless to orange-yellow NO REACTION 5 Solution goes from colourless to red IODINE FORMED 6 The colour change in Experiments 4 and 5 is due to dilution – there is no reaction
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DISPLACEMENT REACTIONS OF HALOGENS
EQUATIONS CHLORINE + SODIUM BROMIDE CHLORINE + SODIUM IODIDE BROMINE + SODIUM IODIDE
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DISPLACEMENT REACTIONS OF HALOGENS
EQUATIONS CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE
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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
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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) NaBr(aq) —> Br2(aq) NaCl(aq)
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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) IONIC EQUATION Cl2(aq) Br¯(aq) —> Br2(aq) Cl¯(aq)
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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) NaI(aq) —> I2(aq) NaCl(aq) IONIC EQUATION Cl2(aq) I¯(aq) —> I2(aq) Cl¯(aq)
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DISPLACEMENT REACTIONS OF HALOGENS
EQUATIONS CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE Br2(aq) NaI(aq) —> I2(aq) NaBr(aq) IONIC EQUATION Br2(aq) I¯(aq) —> I2(aq) Br¯(aq)
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DISPLACEMENT REACTIONS OF HALOGENS
SUMMARY CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE THIS SHOWS THAT A MORE REACTIVE HALOGEN WILL DISPLACE A LESS REACTIVE ONE FROM AN AQUEOUS SOLUTION OF ITS SALT
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DISPLACEMENT REACTIONS OF HALOGENS
EQUATIONS CHLORINE + SODIUM BROMIDE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM IODIDE IODINE + SODIUM CHLORIDE BROMINE + SODIUM IODIDE IODINE + SODIUM BROMIDE THIS SHOWS THAT A MORE REACTIVE HALOGEN WILL DISPLACE A LESS REACTIVE ONE FROM AN AQUEOUS SOLUTION OF ITS SALT HOWEVER, THIS REACTION DOES NOT TAKE PLACE BROMINE + SODIUM CHLORIDE CHLORINE + SODIUM BROMIDE (Bromine is below chlorine in the Group so is less reactive)
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DISPLACEMENT REACTIONS OF HALOGENS
EXPLANATION 17+ 35+ CHLORINE ATOM 17 PROTONS 17 ELECTRONS 2,8,7 BROMIDE ION 35 PROTONS 36 ELECTRONS 2,8,18,8 THE CHLORINE ATOM PULLS AN ELECTRON OUT OF THE OUTER SHELL OF THE BROMIDE ION – THE CHLORINE ATOM BECOMES A CHLORIDE ION AND THE BROMIDE ION BECOMES A BROMINE ATOM. PRESS THE SPACE BAR TO SEE WHAT HAPPENS
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DISPLACEMENT REACTIONS OF HALOGENS
EXPLANATION CHLORIDE ION 17 PROTONS 18 ELECTRONS BROMINE ATOM 35 PROTONS 35 ELECTRONS CHLORINE ATOM 17 PROTONS 17 ELECTRONS BROMIDE ION 35 PROTONS 36 ELECTRONS BECAUSE BROMINE ATOMS ARE LARGER THAN CHLORINE ATOMS, IT IS EASIER TO PULL ONE OF THEIR OUTER SHELL ELECTRONS OUT. CHLORINE NOW HAS THE OUTER SHELL ELECTRONIC CONFIGURATION OF A NOBLE GAS.
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GROUP VII - SUMMARY F Cl Br I F2 Cl2 Br2 I2 2,7 2,8,7 2,8,18,7
FLUORINE CHLORINE BROMINE IODINE SYMBOL F Cl Br I MOLECULAR FORMULA F2 Cl2 Br2 I2 APPEARANCE PALE YELLOW PALE GREEN RED-BROWN GREY-BLACK STATE (room temp) GAS GAS LIQUID SOLID COLOUR OF VAPOUR PALE YELLOW GREEN RED-BROWN PURPLE ELECTRONIC CONFIGURATION 2,7 2,8,7 2,8,18,7 2,8,18,18,7 BOILING POINT INCREASES ION (electronic config) F¯ 2,8 Cl¯ 2,8,8 Br¯ 2,8,18,8 I¯ 2,8,18,18,8 REACTION WITH SODIUM LESS REACTIVE PRODUCT OF REACTION WITH SODIUM SODIUM FLUORIDE (NaF) SODIUM CHLORIDE (NaCl) SODIUM BROMIDE (NaBr) SODIUM IODIDE (NaI)
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QUICK QUIZ ELEMENTS IN GROUP 7 ARE KNOWN AS THE ………
WHAT ARE THE NAMES OF THE ELEMENTS HOW DOES THE ATOMIC NUMBER CHANGE DOWN THE GROUP? HOW DOES THE ELECTRONIC CONFIGURATION CHANGE? HOW DOES THE ATOMIC SIZE (RADIUS) CHANGE? HOW MANY ELECTRONS DO THEY HAVE IN THE OUTER LEVEL? ARE THEY METALS OR NON-METALS? WHAT HAPPENS TO THEIR COLOUR DOWN THE GROUP? DO THEY GO AROUND IN PAIRS OR AS MONATOMIC GASES? WHAT HAPPENS TO THEIR STATE AT ROOM TEMPERATURE? WHAT TYPE OF COMPOUNDS DO THEY FORM WITH METALS? HOW CAN EXPLAIN THEIR RELATIVE REACTIVITY IN TERMS OF THE ATOMIC STRUCTURE?
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QUICK QUIZ - ANSWERS HALOGENS.
FLUORINE, CHLORINE, BROMINE, IODINE, ASTATINE. ATOMIC NUMBER INCREASES DOWN THE GROUP. GET MORE SHELLS DOWN THE GROUP. ATOMIC SIZE INCREASES DOWN THE GROUP. THEY ALL HAVE SEVEN ELECTRONS IN THE OUTER LEVEL. THEY ARE NON-METALS. COLOUR DARKENS DOWN THE GROUP. ATOMS GO AROUND IN PAIRS OR AS DIATOMIC GASES. GO FROM GAS TO SOLID DOWN THE GROUP. THEY FORM IONIC COMPOUNDS WITH METALS. THE LARGER THEY ARE THE LESS EASILY ELECTRONS ARE GAINED AND THE LESS REACTIVE THEY BECOME.
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© 2011 KNOCKHARDY PUBLISHING & JONATHAN HOPTON
GROUP VII The Halogens THE END © 2011 KNOCKHARDY PUBLISHING & JONATHAN HOPTON
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