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  1. Revision sheet Chemistry C1a, Topic 5: Patterns in Properties & Topic 6: Making Changes

  2. PERIODIC TABLE Groups • Groups 1-2 - Alkali metals • Middle of table - Transition metals • Group 7 Halogens • Group 8 or 0 - Nobel gases/inert elements • 1 2 transition metals 3 4 5 6 78or0 NB: Group 8 - Inert/noble gases are unreactive

  3. PERIODIC TABLE SUMMARY • PERIODS – ACROSS GROUPS – GO DOWN H/He – AT THE TOP • Elements in the same group have the similar chemical properties

  4. ELEMENTS, ATOMS AND COMPOUNDS • Element has one type of atom in it e.g. Cl2 or H2 or O2 • Compound has different elements within it e.g. H2O (hydrogen and oxygen) or NH3 (Nitrogen and Hydrogen) • Atom is just one molecule of an element e.g. Cl or H or O

  5. FLAME TEST/Reaction with NaOH GROUP 1 • Potassium- lilac/no precipitate formed • Sodium – yellow/no precipitate formed • Lithium - red flame/white precipitate Group 2 • Calcium - red flame/white precipitate • Barium- green flame Transition metals • Copper – blue/green/ pale blue precipitate • Lead – blue/white/white precipitate • Iron (II) – pale green precipitate • (Higher – Iron (III) – orange precipitate)

  6. TEST FOR THE 5 COMMON GASES • Ammonia – red litmas paper  blue • Chloride – bleaches litmas paper • Carbon dioxide – limewater cloudy • Hydrogen – ‘pop’ with a lit splint • Oxygen – relights a glowing splint • When above is reacted with water • Element + water → Element hydroxide + hydrogen

  7. REACTIVITY SERIES • Most reactive  least reactive • caesium Cs  rubidium Rb  potassium K sodium Na  lithium Li  calcium Camagnesium Mg aluminium Al zinc Zn iron Fe Gold Au silver Ag • RULE: An metal is more reactive if it is further to the left of the periodic table or further down in the group (not including groups 3-8)

  8. METAL ORES • Most metals are found in ores • Metal have to be separated from their oxides • They are extracted using two methods (linked to the reactivity series) • Electrolysis – K, Na, Ca, Mg Al (reactive) • Reacting with carbon – Zn, Fe, Sn & Pb (less reactive)

  9. TYPES OF REACTIONS • PHYSICAL – changing of states • EXOTHERMIC – gives out heat • ENDOTHERMIC – take in heat from it surrounding • THERMAL DECOMPOSITION – is a chemical reaction where a single compound breaks up into two or more simpler compounds or elements when heated • DEHYDRATION – chemical reaction that has water as a product • HYDRATION – have water as a reaction

  10. SALTS • Chemical name for common salt is sodium Chloride • acids with alkali = neutralisation • oxides, hydroxides and carbonates all react with acids to produce salts • insoluble salts are prepared by mixing two solutions and forms a precipitate • ACID + METAL HYDROXIDE/OXIDE  SALT + WATER = NEUTRALISATION

  11. HIGHER - Protons, electrons and neutrons • Number of Protons = atomic number of the element (in top left hand corner of the periodic table) • Number of Electrons = Protons • Number of Neutrons = Mass Number - Atomic Number – Therefore can be different

  12. HIGHER - Reactivity Halogens • Fluorine (atomic number 9) > Chlorine (atomic number 17) > Bromine (atomic number 35) >Iodine (atomic number 53) • Therefore chlorine will displace Bromine and Iodine • Same electron in outer shell give similar chemical properties • As the atomic numbers of the halogens increase, they become less reactive