Presentation on theme: "Physical properties of metals and their uses Miss Jan."— Presentation transcript:
Physical properties of metals and their uses Miss Jan
Physical properties of metals SLOs understand how the uses of metals are based on their properties Know these terms: electrical conductivity, thermal conductivity, density, ductility, lustre, and malleability understand how the crystal structure of metals can explain their physical properties be able to name some common alloys understand why alloys are useful
Physical Properties of some metals (Worksheet) MetalSymbolAtomic mass Melting point ( C) State at 25 C Density (g cm –3 ) Magnesium Aluminium Iron Copper Zinc Silver Gold Mercury201– Lead Mg Al Fe Cu Zn Ag Au Hg Pb Solid Liquid
3. Why is Mercury an unusual metal? It is the only metal that is liquid at room temp 4. List the metals in the table in order of increasing melting points. Hg, Pb, Mg, Al, Ag, Au, Cu, Zn, Fe 5. Which metal has the lowest melting point? Which has the highest melting point? Lowest: Hg, Highest: Fe
6. List the metals in order of increasing density. Mg, Al, Zn, Fe, Cu, Ag, Pb, Hg, Au 7. Which metal has the highest density? Which has the lowest density? Highest: Au, Lowest: Mg 8. Is there a general relationship between density and atomic mass? Generally, as the atomic mass increases, the density increases
Use NMS 2 page 52 to complete the table on the worksheet Metals areThis means theyThis is used inWhich are made of SonorousMake a ringing sound when hit Cymbals in an orchestra Brass, steel Lustrous Malleable Ductile Solids with high melting points Good conductors of heat Good conductors of electricity
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Metals areThis means they This is used in Which are made of Sonorous Make a ringing sound when hit Cymbals in an orchestra Brass, steel Lustrous Malleable Ductile Are shiny Can be beaten into shape without shattering Silver, Gold Mirror/ Jewellery Car bodiesSteel Can be stretched out to form a wire Wires Steel
Metals areThis means they This is used in Which are made of Solids with high melting points Good conductors of heat Good conductors of electricity Can withstand heat Heating elements Nickel alloys Transmit heat easily Steel, aluminium, Copper Pots and pans Allows electricity to pass through Electrical wires Copper
Crystal structure of metals
Atoms packed tightly (lattice) Strong forces between atoms makes metal strong and hard to melt. Outer electrons (valence e - ) free to move about this is how metals conduct heat and electricity Moving electrons also reflect light lustre
Alloys Mixture of metals Have different properties to the original pure metal from which it was made from E.g. Amalgam: mercury with another metal (metal fillings)
Brass (Cu + Zn) – easy to shape
Steel (Fe + C) and Bronze (Cu + Sn) – stronger, resist corrosion
Alloys worksheet - True or false? 1.True 2.True 3.False: steels are alloys of iron 4.False: Bronze contain copper and tin 5.True 6.True 7.False: Brass is a very hard alloy 8.True 9.False: magnets are made of iron, nickel and cobalt
Photograph of a man sitting on a pool of mercury Mercury is so dense, and clings to itself so strongly, than the man floats on it like styrofoam floats on water.
NMS 2 Page Uses of metals MetalUseProperties AluminumCooking foil1. Easily rolled into thin sheets. 2. Doesn’t melt in the oven. GoldJewellery1. Attractive colour. 2. Doesn’t corrode. CopperElectrical wiring 1. Good conductor of electricity. 2. Easily drawn into wires. ChromiumBathroom fittings 1. Shiny. 2. Doesn’t corrode. LeadPipes1. Soft. 2. Melts easily. 3. Doesn’t corrode.
2.An alloy is a mixture of two or more metals. 3. Alloys are used because they have more useful combinations of properties than pure metals. 4.See table, p. 53, and the worksheet on alloys.