2Physical Properties of Metals DuctileMalleableGood conductors of electricityGood conductors of heatShinyHigh melting points & boiling pointsHigh densityStrength
3Structure of Metals Metals are generally solids. [Recall: Particulate Models of Matter]Simplified diagram of a metal:
4Structure of Metals: Explanation Metals have high density because there is little empty space between the atoms.Atoms are packed close together in a metal.
5Structure of Metals: Explanation In pure metals, atoms of the same size are packed regularly in layers.Metals are malleable and ductile because the layers of atoms can slide over each other easily when a force is applied.Push
6Exceptions! Group I metals: Mercury: Low melting point Low density (it floats on water)Mercury:Liquid at room temperature
7Differentiating Metal & Non-Metal All metals conduct electricity.
9Would you use pure metal or an alloy to make your armour? If you were a SPARTAN..Would you use pure metal or an alloy to make your armour?
10Alloys Mixtures of a metal with another element For example, Bronze: copper and tinBrass: copper and zincStainless steel: iron, chromium, nickel and carbon
11Arrangement of atoms in alloy AlloysIn an alloy, the atoms have different sizes.Arrangement of atoms in alloy
12Alloys The different sizes of the atoms disrupts the orderly layers of atoms, andmakes it more difficult for the layers to slide over each other.PUSH
13Metals are often used in the form of alloys because.. They are harder and stronger.PUSH
14Metals are often used in the form of alloys because.. They are more resistant to corrosion.E.g. Brass [copper, zinc] is more resistant to corrosion than pure copper.It lowers the melting points of metals.E.g. Solder [tin, lead] has lower m.p. than pure tin or pure lead, and can be used to join metals.It improves the appearance.E.g. Pewter [Tin, antimony, copper] looks more beautiful than pure tin.
15Some alloys.. Uses Properties Composition Alloy Brass Stainless Steel Decorative ornamentsBright, shiny, looks like silverTin, antimony, copperPewterFor joining metalsLow melting pointTin, leadSolderCutlery, utensilsResistant to corrosion, strongIron, chromium, nickel, carbonStainless SteelCoins, musical instrumentsDoes not corrode easily; looks like goldCopper, zincBrassUsesPropertiesCompositionAlloy
16Do you think metals react in the same manner? Question!Do you think metals react in the same manner?
17Metals may react more or less violently than others the metal that reacts more vigorously is said to be more reactive than the other metalmetals have different reactivities
18Reactivity Series of Metals An arrangement of metals in order of their ease of reaction, beginning with the most reactiveThe position of a metal in the series determinesReactions of the metal with various reagentsDisplacement of one metal from its compound by another metalMethod of extraction of a metal from its ore.
19MetalReaction with waterSodiumReacts very fast with cold water, sometimes with explosion, produces sodium hydroxide and H2(which may catch fire and explode)PotassiumExplodes with cold water, potassium hydroxide and H2 produced a lot of heat given off, H2 gas burns in airCalciumReacts readily with cold water, calcium hydroxide obtained together with lots of bubbles of H2ZincNo reaction with cold water; hot zinc burns in steam to produce zinc oxide and H2IronNo reaction with cold water, rusting occurs slowly in the presence of air. Red hot iron reacts slowly with steam to produce iron oxide and H2SilverNo reaction under any conditionCopperMagnesiumReacts very slowly with cold water; a few bubbles of H2 gas produced; magnesium hydroxide solution obtained. Hot magnesium burns to produce magnesium oxide and hydrogen gas; H2 burns in air.
21Revealing the True Order PotassiumSodiumCalciumMagnesiumZincIronHydrogen is inserted as a reference pointMetals above H: Reacts with HCl and water/steamMetals below H: No reaction with HCL and water(Hydrogen)CopperSilver21
22Write the Chemical Equation! Reaction with water/steamMetal + (cold) Water Metal hydroxide + HydrogenExample:Potassium + Water Potassium hydroxide + Hydrogen2K(s) + 2H2O(l) 2KOH(aq) +H2(g)Metal + Steam Metal oxide + HydrogenMagnesium + Steam Magnesium oxide + HydrogenMg(s)+ H2O(g) MgO(s) + H2(g)
23Write the Chemical Equation! Reaction with dilute hydrochloric acidMetal + Hydrochloric acid Metal chloride + HydrogenExample:Magnesium + Hydrochloric Acid Magnesium chloride + HydrogenMg(s) + 2HCl(aq) MgCl2(aq) + H2(g)
24Most reactive Reactivity increases Least reactive PotassiumSodiumCalciumMagnesiumAluminiumZincIronTinLead(Hydrogen)CopperSilverGoldPleaseStopCallingMeAZebraIThinkLarryHooCanSeeGirlsMost reactiveReactivity increasesLeast reactive24
25Be Creative! Come up with your set of mnemonics Share it with the class!5mins to Brainstorm
26The Position of Aluminium Aluminium does not appear to react with water or steam.Shouldn’t it be lower in the reactivity series?
27The Position of Aluminium A thin layer of aluminium oxide protects the metal from reacting.What happens when this layer of oxide is removed?Aluminium will react with steam a little less vigorously than magnesium, according to the reactivity series.
28Using the Reactivity Series Predict chemical reactions of metalsE.g.Copper does not react with water under any condition.We can predict that gold will also have no reaction with water since it is less reactive than copper.
29Reactivity Series: An explanation When metals react with water/dilute acid, they lose electrons to become ions.The more readily a metal gives up electrons to form ions, the more reactive it is.Reactivity Series: A measure of how easily a metal gives up electrons to form positive ions.
31Valence electron escapes easily Down a GroupAtom becomes biggerIncrease in number of electron shellsValenceelectron (-)+Strong attractive force between nucleus and valence electronNucleusNucleusWeaker attractive force between nucleus and valence electron+Valence electron (-)Valence electron escapes easily
32Across a Period Metals Non-metals Increase in tendency to lose electrons rather than gain electronsSodiumChlorine
34SummaryThe higher the metal in the reactivity series, the more reactive the metalThe more reactive the metal, the more violent are the reaction with HCl and waterReaction of metal with HClMetal + HCl Metal chloride + HydrogenReaction of metal with water/steamMetal + Water Metal hydroxide + HydrogenMetal + Steam Metal oxide + Hydrogen