Elements and compounds

• Atoms


  Tiny building blocks that everything around us is made up of
• Element


  A substance that is made up of one type of atom
• Compound


  Two or more types of atoms , chemically joined to each other
• Groups


  -Verticle columns

  -Similar properties

  -1 to 0 (No 8)
• Periods


  Horizontal rows that tell you how many shells an element has
• Where are metals on the periodic table

  Left and centre
• Where are non metals om the periodic table

  Right
• Metals


  • Sonorous
  • Can be bent into shape
  • Shiny
  • Strong
  • Same magnetic properties
  • High boiling point
  • High melting point
  • Good conductors of electricity
  • Good conductors of heat
• Non-metals


  • Low density (light)
  • Brittle (breaks easily)
  • Not bendy
  • Bad conductors of heat
  • Low boiling point
  • Low melting point
  • Bad conductors of electricity
  • Some are gases at room temperature
• Malleable


  Easy to hammer into thin sheets
• Sulphur conducts electricity
• Metals are magnetic
• Molecule


  Two or more atoms of the same type joined together chemically (O2, H2, N2)
• Mixture


  Two or more types of atoms that are mixed together but not chemically joined
• -ide


  Two elements of non metal
• -ate


  Two elements plus oxygen
• Formula


  Uses symbols
• Metal and acid


  Metal + acid --> salt + hydrogen
• Naming salts


  First part - metal

  Second part - acid

  Hydrochloric acid > metal chloride salt

  Sulphuric acid > metal sulphate salt

  Nitric acid > metal nitrate salt
• Corrosion


  When metals react with oxygen to form oxides in the presence of water
• Rusting


  Corrosion of iron
• Signs of a chemical reaction

  -Gas is produced

  -Light is produced

  -Temperature change

  -Change of colour
• Oxidation


  When oxygen is added to an element
• Combustion (burning) always has oxygen added to the substance
• Conservation of mass


  The total mass of reactants = the total mass of products
• Thermal decomposition


  The breaking down of a substance using heat
• When a metal carbonate is heated , it breaks down to produce a metal oxide and carbon dioxide
• Test for CO2


  Limewater
• Test for hydrogen


  Squeaky pop test
• Exothermic reactions


  Heat energy is given out to the surroundings (temperature rises)
• Endothermic reactions


  Heat is being taken in from surroundings (temperature drops)
• More heat energy is taken in to break old bonds in the reactants than it is to be released to make new bonds in the products
• Metal and water


  Metal + water --> metal hydroxide + hydrogen

  (sodium + water)

  2Na + 2H2O > 2NaOH + H2
• Displacement reaction


  When a more reactive metal displaces are less reactive metal from its compound to form a new compound
• Potassium

  Sodium

  Calcium

  Magnesium

  Aluminium

  Zinc

  Iron

  Lead

  Copper

  Silver

  Gold
• The more reactive a metal, the quicker it corrodes
• How to prevent rusting

  -Coat with plastic

  -Paint the metal

  -Cover with oil

  -Galvanise (coat with zinc)