Topic 9: Metals

• Strong • Malleable • Ductile • Sonorous • Shiny • Good conductors of heat and electricity • High Density • High melting and boiling points.

• Dull • Low density • Weak • Brittle • Poor electrical conductors • Poor thermal conductors • Makes dull sound • Non-magnetic

Metal + Acid —-> Salt + Hydrogen How vigorously they react depends on where they are placed in the reactivity series.

Metal + Oxygen —–> Metal oxide Some metals are so reactive that they must be kept under oil to prevent reaction from occurring. They can also be burnt using a Bunsen burner.

sodium + water —-> sodium hydroxide + hydrogen 2Na + 2H2O —> 2NaOH + H2

magnesium + steam —–> magnesium oxide + hydrogen Mg + H2O —-> MgO + H2

manufacture of aircraft –> strong, lightweight overhead electricity cables –> good conductor of electricity, ductile, resists corrosion cooking foil and food cartons –> non toxic, resistant to corrosion, can be rolled into thin sheets drink cans –> light, non-toxic, resistant to corrosion coating CDs and DVDs –> can be deposited as a thin film, shiny surface reflects laser beam

electrical wiring –> one of the best conductors of electricity, ductile saucepans and saucepan bases –> malleable, conducts heat well, unreactive, tough

A mixture of two elements, on of these being a metal

They often have properties that are different to the elements they contain, making them more useful than pure elements alone. These differences may include hardness, tensile strength, malleability, melting point etc.

Copper and zinc.

It is corrosion-resistant and harder than the elements it is made up of.

Iron and a non-metal carbon.

Iron, carbon, chromium and nickel. Chromium prevents the steel from rusting Nickel makes it harder.

They are made up of atoms of different sizes rather than bein uniform. This means that the layers of atoms cannot slide over each other easily, making the whole alloy much stronger than any of the pure metals. They tend to have better corrosion resistance They are more versatile for manipulating into different forms.

Properties: Easily worked Lost most of the brittleness Uses: Car bodies Large structures Machinery

Cutting tools, Chisels Razor blades

Drill bits Spring

Cutlery, Kitchen sinks Surgical instruments Chemical plant reaction vessels

Edges of high-speed cutting tools

potassium sodium calcium magnesium aluminium carbon zinc iron tin lead hydrogen copper silver gold platinum

A more reactive metal displaces a less reactive metal from a compound. Metals below aluminium in the reactivity series can be reduced by carbon while the oxides of metals above zinc in the reactivity series cannot be reduced by carbon. These metal oxides are very stable and can be reduced by electrolysis.

very violent with cold water catches fire

violent with cold water