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 alloysunderstand why alloys are useful

Physical Properties of some metals (Worksheet)

Metal Symbol Atomic mass

Melting point (C)

State at 25C

Density (g cm–3)

Magnesium 24 650 1.7

Aluminium 27 660 2.7

Iron 56 1535 7.8

Copper 64 1083 8.9

Zinc 65 1500 7.1

Silver 108 961 10.5

Gold 197 1063 19.3

Mercury 201 –39 13.6

Lead 207 327 11.3

Mg

Al

FeCu

Zn

AgAu

HgPb

SolidSolidSolid

Solid

Solid

Solid

Solid

SolidLiquid

3. Why is Mercury an unusual metal?It is the only metal that is liquid at room temp4. List the metals in the table in order of increasing melting points.Hg, Pb, Mg, Al, Ag, Au, Cu, Zn, Fe5. 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, Au7. Which metal has the highest density? Which has the lowest density?Highest: Au, Lowest: Mg8. 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 are This 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

Solids with high melting points

Good conductors of heat

Good conductors of electricity

Brainpop

http://www.brainpop.com/science/matterandchemistry/metals/

Metals are This 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 bodies Steel

Can be stretched out to form a wire

Wires Steel

Metals are This 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

AlloysMixture of metals Have different properties to the original

pure metal from which it was made fromE.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. True2. True3. False: steels are alloys of iron4. False: Bronze contain copper and

tin5. True6. True7. False: Brass is a very hard alloy8. True9. 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 52-53

1.Uses of metalsMetal Use Properties

Aluminum Cooking foil 1. Easily rolled into thin sheets.2. Doesn’t melt in the oven.

Gold Jewellery 1. Attractive colour.2. Doesn’t corrode.

Copper Electrical wiring

1. Good conductor of electricity.2. Easily drawn into wires.

Chromium Bathroom fittings

1. Shiny.2. Doesn’t corrode.

Lead Pipes 1. 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.