All State the forms in which an ionic compound can conduct electricity Most Describe how ionic compounds conduct electricity Some Use ionic equabons to show how ions form Ionic Liquids STARTER: Draw the diagram of an ionic lahce structure. Explain why the ions cannot move around. 06/05/15
All State the forms in which an ionic compound can conduct electricity Most Describe how ionic compounds conduct electricity Some Use ionic equabons to show how ions form Ions Revision
Ions Revision For the following atoms, describe how they form the corresponding ions a) Ag à Ag + b) Mg à Mg 2+ c) F à F - d) N à N 3- EXAMPLE: Na (sodium) atoms forms a Na + ion by losing 1 electron Extension: If you feel confident, predict what ions the following atoms will form using their electronic structure or posibon in periodic table a) Ca b) Cl c) K
All State the forms in which an ionic compound can conduct electricity Most Describe how ionic compounds conduct electricity Some Use ionic equabons to show how ions form Ionic EquaBons We can write the loss or gain of electrons as an equabon like this: Sodium atoms (Na) lose 1 electron to become a sodium ion (Na + ) Na à Na + + e - Copper atoms lose 2 electrons to become copper ions Cu à Cu 2+ + 2e -
All State the forms in which an ionic compound can conduct electricity Most Describe how ionic compounds conduct electricity Some Use ionic equabons to show how ions form Ionic Liquids
Copy and complete using the words in green: When a ionic compound in water, the breaks up. The ions and are free to move around rapidly. The ions can carry electrical through the. The solubon therefore conducts electricity. WORDS: separate dissolves lahce soluble solubon charge Extension: Draw a diagram to show how the solubon would differ if it were more concentrated
All State the forms in which an ionic compound can conduct electricity Most Describe how ionic compounds conduct electricity Some Use ionic equabons to show how ions form Progress check Can you answer the following quesbons? GRADE: C B A Extension: Water is made up of covalent molecules. Does it conduct? Why is it not safe to have near electrical equipment?
Starter Water is made up of covalent molecules. Does it conduct? Why is it not safe to have near electrical equipment?
Electrolysis splihng up compounds using electricity Electrode rod that conducts electricity come in pairs one negabve and one posibve. Electrolyte ionic liquid or solubon broken down by electrolysis.
Opposites acract NegaBve ions move to the posibve electrode e.g. chloride. Electrode rod that conducts electricity oden made of graphite or plabnum they are inert. PosiBve ions move to the negabve electrode e.g. copper.
Don t PANIC - Positive is Anode, Negative Is Cathode.
What did we see happening yesterday?
List the products of the electrolysis of these molten salts. Salt Anode (+) Cathode (- ) Potassium Bromide Aluminium Oxide Barium Iodide Sodium Chloride Calcium Fluoride
List the products of the electrolysis of these molten salts. Salt Anode (+) Cathode (- ) Potassium Bromide Bromine Potassium Aluminium Oxide Oxygen Aluminium Barium Iodide Iodine Barium Sodium Chloride Chlorine Sodium Calcium Fluoride Fluorine Calcium
Electrolysis of Lead Bromide
At the negabve electrode (cathode) PosiBve lead ions, Pb 2+, are acracted to the negabve electrode. At the negabve electrode, the ions collect electrons from the circuit. The lead ion turns back in to a lead atom.
At the posibve electrode (anode) At the posibve electrode, bromide ions, Br -, lose electrons (to replace electrons taken by the lead). The bromide ions combine to make bromine gas molecules.
Using ionic liquids à Electrolysis Use the diagram to describe what happened with the demo of lead bromide.
ApplicaBon
Marking
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Electrolysis Copper Sulphate solubon CuSO 4(aq) PredicBon. What do you think is going to happen? ObservaBon. What do you see? Record your results Conclusion. Can you explain what you have seen?
All Name products formed by electrolysis of molten solids Most Describe the process of electrolysis of aluminium Some Use half equabons to show the reacbons at electrodes To predict the products of electrolysis 1. Find the correct ions your data sheet 2. IdenBfy which ion will go to which electrode (posibve or negabve) 3. Metal ions will form a molten metal, non- metals will usually form a gas and is normally 2 atoms in a molecule (e.g. F 2 or Br 2 ) Electrolysis e.g. Lead Bromide 1. Pb 2+ Br - 2. Pb 2+ goes to negabve electrode, Br- goes to posibve electrode 3. Molten lead (Pb) is formed at negabve electrode, Bromine gas (Br 2 ) is formed at posibve electrode
OILRIG - OxidaBon and ReducBon O oxidabon I is L loss R reducbon I is G gain When an atom loses electrons, this is called oxidacon. When an atom gains electrons, this is called reduccon. Both processes happen in electrolysis.
Complete the table, you may choose FOUNDATION where to begin: HIGHER Extension: Where is oxidabon happening? Where is reducbon happening? Use OILRIG to help Hint: Remember to balance the electrons How many Br - ions in total are needed to make Br 2? How many electrons in total are lost?
Complete the table, you may choose FOUNDATION where to begin: HIGHER
All State the forms in which an ionic compound can conduct electricity Most Describe how ionic compounds conduct electricity Some Use ionic equabons to show how ions form Ionic EquaBons A sodium ion (Na +) gains an electron Na + + e - à Na Bromide ion loses an electron to become Br 2 Br - à Br 2 + e - Is this correct??
All State the forms in which an ionic compound can conduct electricity Most Describe how ionic compounds conduct electricity Some Use ionic equabons to show how ions form Ionic EquaBons Bromide ions lose electrons to become Br 2 2Br - à Br 2 + 2e - Each bromide ion loses 1 electron, in total 2 electrons are lost!
OILRIG Cl - Cl - OxidaCon is loss, reduccon is gain OILRIG Na + Na + Cl - Cl - Na + Na + - ions LOSING electrons to become atoms is called OXIDATION (even though oxygen may not be involved) + ions GAINING electrons to become atoms is called REDUCTION
All Name products formed by electrolysis of molten solids Most Describe the process of electrolysis of aluminium oxide Some Use half equabons to show the reacbons at electrodes Uses of Electrolysis
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All Name products formed by electrolysis of molten solids Most Describe the process of electrolysis of aluminium oxide Some Use half equabons to show the reacbons at electrodes Aluminium Oxide GeHng aluminium from aluminium oxide (ore)
All State ions present in solubons of compounds Most Describe how the products are different for solubons Some Use the rules to idenbfy products for different solubons Electrolysis of SoluBons So far we have looked at electrolysis of a molten compound What happens when we have solucons? (i.e. including water)
What happens when the ionic compounds are dissolved in water? Here, water molecules break up into HYDROGEN IONS, H + and HYDROXIDE IONS OH - H 2 O è H + + OH - So, in an ionic solubon (eg sodium chloride solubon), there will be FOUR types of ion present: TWO from the ionic compound and TWO from the water (H + + OH - ) SODIUM CHLORIDE SOLUTION NaCl (aq) H + Cl - OH - H + Na + Na + OH - Na + H + Cl - OH - Cl -
IONIC SOLUTION H + Cl - OH - H + Na + OH - H + OH - Na + Cl - Na + Cl - Which ions gain or lose electrons ( get discharged ) and which stay in solubon?
IONIC SOLUTIONS: At the CATHODE Na + sodium ION, missing 1 electron + H + hydrogen ION, missing 1 electron H Hydrogen ATOM, NEUTRAL which ions? As HYDROGEN is LESS REACTIVE than SODIUM, it is discharged. The sodium ions stay in solu0on. Na + H H + H H + Na + At CATHODE: 2H + + 2e - H 2
IONIC SOLUTIONS: At the CATHODE halogen compounds hydroxide ION, chloride ION, Cl - O H from water extra chlorine ATOM, extra 1 electron Cl electron NEUTRAL + H H O O Cl - Cl - O Cl - Cl - H O H If the ion is a HALOGEN (Cl, Br, I) it is discharged and chlorine (or Br or I) is given off and the OH - ions stay in solu0on which ions? At ANODE: 2Cl - 2e - + Cl 2
IONIC SOLUTIONS: CATHODE non halogen compounds hydroxide ION, OH - nitrate ION, extra 1 NO - 3 O H from water, extra electron electron + O Oxygen atom NO - 3 H O NO - 3 NO - 3 O H NO - 3 If the ion is NOT a halogen (eg nitrate, sulphate etc) then the HYDROXIDE ions from the water are discharged to make WATER and OXYGEN gas. The other ions stay in solubon. H O O H which ions? At CATHODE: 4OH - 2H 2 O + O 2 + 4e -
RULES FOR IONIC SOLUTIONS + ANODE Acracts ions ( Anions ) - CATHODE Acracts + ions ( CaBons ) If ions are HALOGENS ie chloride Cl - bromide Br - iodide I - the is produced. If ions are NOT HALOGENS Eg sulphate SO 4 2-, nitrate NO 3- carbonate CO 3 2- is produced. If + ions (metals) are K, Na, Ca, Mg, Zn, Fe Then is produced If + ions (metals) are LESS REACTIVE than hydrogen Cu, Ag, Au Then the is produced
RULES FOR IONIC SOLUTIONS + ANODE Acracts ions ( Anions ) - CATHODE Acracts + ions ( CaBons ) If ions are HALOGENS ie chloride Cl - bromide Br - iodide I - the HALOGEN is produced. If ions are NOT HALOGENS Eg sulphate SO 4 2-, nitrate NO 3- carbonate CO 3 2- OXYGEN is produced. If + ions (metals) are MORE REACTIVE than hydrogen K, Na, Ca, Mg, Zn, Fe Then HYDROGEN is produced If + ions (metals) are LESS REACTIVE than hydrogen Cu, Ag, Au Then the METAL is produced
(REACTIVITY: K + Na + Ca 2+ Mg 2+ Al 3+ Zn 2+ Fe 3+ H + Cu 2+ Ag + Au 3+ ) Compound State Ions Cathode (-) Anode (+) potassium chloride aluminium oxide copper chloride sodium bromide silver nitrate molten K + Cl - potassium chlorine molten solucon solucon solucon potassium chloride solucon zinc sulphate solucon (REACTIVITY: K + Na + Ca 2+ Mg 2+ Al 3+ Zn 2+ Fe 3+ H + Cu 2+ Ag + Au 3+ )
(REACTIVITY: K + Na + Ca 2+ Mg 2+ Al 3+ Zn 2+ Fe 3+ H + Cu 2+ Ag + Au 3+ ) Compound State Ions Cathode (-) Anode (+) potassium chloride molten K + Cl - potassium chlorine aluminium oxide molten Al 3 + O 2 - aluminium oxygen copper chloride solucon Cu 2 + Cl - H + OH - copper chlorine sodium bromide solucon Na + Br - H + OH - hydrogen bromine silver nitrate solucon Ag + NO 3 - H + OH - silver oxygen potassium chloride solucon K + Cl - H + OH - hydrogen chlorine zinc sulphate solucon Zn + SO 2-4 H + OH - hydrogen oxygen (REACTIVITY: K + Na + Ca 2+ Mg 2+ Al 3+ Zn 2+ Fe 3+ H + Cu 2+ Ag + Au 3+ )