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Chapter 6 Metals and Non-Metals:

Uses of Metals:

There are many uses of metals. For Example:

 

  1. Tungsten is used in lightbulbs

  2. Copper is used in plumbing and wiring

  3. Large quantities are used in the production of stainless steel

  4. Steel is used in car bodies

Properties of Metals and Non-Metals:
Left: Copper wiring is used due to coppers good conductive ability
 
Right: Steel is also used in car bodies

Metals:                                                                    Non-Metals:

 

-Some metals can be magnetised                     - Non-Metals are soft and easy tocut

 

-Most are hard (except potassium                     - Poor conductor of electricity (except pencil)

 and sodium)

                                                                               - Many are gases (some solid/liquid at room temperature)

-Good conductors of heat and electricity

                                                                               - Dull appearance

-All are solid at room temperature 

(except mercury)                                                  - Break/shatter when stretched/hammered

 

-Shiny appearance when polished                     - Usually low density 

(lustrous)

                                                                                - Usually low melting point and boiling point

-They can be hammered into sheets

(malleable) and stretched into wires                 - None are magnets

(ductile)

 

-Usually high density

 

-Usually high melting Points

 

Points to know on metals:

  • An alloy is a mixture of metals. Some alloys also contain the non-metal carbon

  • Some common alloys are bronze (copper and tin), steel (iron and carbon), solder (led and tin) and brass (copper and zinc)

  • Alloying one metal with another increases the strength of the metal

Left: Bronze is used to make items such as coins and turbines
 
Right: Solder as you can see is used in wiring
Alkali Metals (3)

  • The three alkali metals we study are lithium, potassium and sodium. They are called alkail metals because they reacts with water to form base solutions

  • Alkali metals do not occur freely in nature because they are so reactive. They easily form compounds i.e all alkali metals are found in their compound (electrolysis)

 

Physical Properties:

  1. Easily cut and shiny when cut

  2. Low densities (float in water)

  3. Low melting points

  4. Good conductor of electricity

 

Chemical Properties:

  1. All alkai metals react easily with air and water

  2. All of the alkali metals lose their shine when they react with air-They tarnish in air (this is why they are covered in oil)

  3. The alkali metals reacts vigoursly in water. For example sodium melts into a ball when dropped in water

  4. When alkali metals react with water they give off hydrogen

  5. The metals burn in air to produce brightly coloured flames

Corrosion of Metals:

  • Corrosion is the undesired process by which a metal is turned into its compound

  • Corrosion occurs when metal reacts with water and oxygen

  • Metal+Oxygen+Water= Iron Oxide i.e rust

  • Metals often increase in mass when they rust

Due to this exposure to air the handle has rusted
Methods of Preventing Rust

  • (i) Galvanising: Zinc is a metal which does not rust. By coating a metal in zinc or galvanising it it will not rust

  • (ii) Painting: This prevents the oxygen and water coming into contact with the metal

  • (iii) Oil or grease: This forms a layer preventing exposure to water or oxygen

© 2016 by Vincent Savage and John Harrington. Young Scientists and Historians

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