MetalsMetalsKnow some properties of metals

Describe metallic bondingState advantages and disadvantages of recyclingRecall uses for iron, copper and aluminium

explain why the bonding arrangement gives metals their properties

PropertiesProperties

Conduct electricity and heatConduct electricity and heat MalleableMalleable DuctileDuctile HardHard High melting and boiling pointsHigh melting and boiling points

IronIron Hard and toughHard and tough Used for car bodiesUsed for car bodies

CopperCopper Good conductor of heat and Good conductor of heat and

electricityelectricity Used for saucepan bottoms and Used for saucepan bottoms and

wiringwiring

AluminiumAluminiumResistant to corrosionResistant to corrosion

Low densityLow density

Used for greenhouse frames and Used for greenhouse frames and aeroplane bodiesaeroplane bodies

Metallic BondingMetallic Bonding In a piece of metal, all the atoms lose In a piece of metal, all the atoms lose

their outer electrons to gain full shells, their outer electrons to gain full shells, and become positive ions. and become positive ions. These These negative electrons move around negative electrons move around between the metal ionsbetween the metal ions. The negative . The negative electrons electrons attractattract the positive ions, the positive ions, making the structure making the structure strongstrong. Metals are . Metals are good at good at conductingconducting electricity and heat electricity and heat because of the free electrons which are because of the free electrons which are able to move around.able to move around.

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Metallic BondingMetallic Bonding

RecyclingRecycling Advantages –Advantages – Saves moneySaves money Less damage to environmentLess damage to environment Uses less energyUses less energy Less poisonous wasteLess poisonous waste Disadvantages-Disadvantages- Scrap metal must be collectedScrap metal must be collected Metal must be sorted from other materialsMetal must be sorted from other materials Difficult if metals in small quantitiesDifficult if metals in small quantities Depends on the public sorting their rubbishDepends on the public sorting their rubbish

AlloysAlloys These are mixtures of two or more These are mixtures of two or more

metalsmetals E.g. brass, duralumin, solderE.g. brass, duralumin, solder The properties are different from the The properties are different from the

base metals base metals

Complete the following sentences, using words Complete the following sentences, using words from the box.from the box.

aa There are strong forces between ions, so There are strong forces between ions, so metals are ____________________________ .metals are ____________________________ .

bb The electrons have a _______________ , and The electrons have a _______________ , and some of them can move, so metals some of them can move, so metals _______________ electricity._______________ electricity.

cc Rows of ions can move over each other, so Rows of ions can move over each other, so metals are _______________ .metals are _______________ .

dd Some _______________ can move, so metals Some _______________ can move, so metals are good at _______________ heat.are good at _______________ heat.

charge conduct conducting charge conduct conducting electrons malleable strongelectrons malleable strong

Metals are used for many different things because they Metals are used for many different things because they have useful properties. have useful properties.

AA malleable (can be hammered or bent into shape)malleable (can be hammered or bent into shape)BB conduct electricityconduct electricityCC conduct heatconduct heatDD strongstrong

For each of the uses below, write down the letter (or letters) of the properties that are useful. Sometimes there may be more than one useful property. For example, saucepans – C (saucepans are made of metal because metals conduct heat).

aa electrical wires __________________electrical wires __________________bb bridges ________________________bridges ________________________cc radiators _______________________radiators _______________________dd cars ___________________________cars ___________________________