Content

• Acids 


  Produce hydrogen ions (H+) in aqueous solutions. They have a pH range of 0-6
• Alkali


  Alkalis produce hydroxide ions (OH-) in aqueous solutions

  They have a pH range of 8-14
• Base


  A substance that can neutralise and acid
• Reaction of metals with oxygen

  When metals react with oxygen we form the metal oxide and an oxidation reaction occurs

  The metal atoms have been oxidised
• Filtration 


  Filtration is used to separate a mixture of an insoluble solid and liquid .

  This is done through filter paper cone and conical flask
• Distillation 


  Used to separate a solvent from the solution

  To perform distillation, the solution is poured into a round-bottomed flask, connected to a water-cooled condenser all in a closed system to prevent the loss of gasses. The solution is heated causing the liquid solvent to boil and turn from liquid to gas. The gas passes through the condenser, is cooled, and condenses back into a liquid (called the distillate), which is collected. The solid solute remains as residue on the inside of the round-bottomed flask.
• Evaporation is used to separate out the solute from a solution, e.g. to separate salt from salt water solution.

  To perform evaporation, the solution is poured into an evaporating basin and heated. The liquid solvent boils off, leaving the solid solute as residue in the evaporating basin. 
• Crystallisation is also used to separate out a solute from a solution, e.g. to separate salt from salt water solution.

  To perform crystallisation, the solution is poured into an evaporating basin and gently heated, causing liquid solvent to evaporate, until crystals start to form. The evaporating basin is then removed from the heat and allowed to slowly cool, encouraging the formation of crystals of the solute in residual solution. Once cool, any remaining solution can be removed by filtration, and the crystals patted dry.
• Fractional distillation is used to separate a mixture of two or more liquidswith different boiling points, e.g. the separation of a mixture of different hydrocarbons in crude oil.
• Chromatography can be used to separate mixtures according to the solubility of the components
• Plum pudding model 


  The discovery of the electron led to the plum pudding model of the atom. The plum pudding model suggested that the atom was a ball of positive charge with negative electrons embedded in it
• Nuclear model 


  Replaced the plum pudding model, the experiment showed that all the mass an atom was in the centre. The electrons were thought to orbit the nucleus
• Bohr Model 


  Neil Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances. The electrons are on energy levels
• Chadwick 


  His work showed the existence of neutrons
• Noble gases 


  The elements in group 0 are called the noble gases. They are unreactive and do not easily form molecules because they have a full outer shell.

  The boiling points increase as you go down the group

  There are weak intermolecular forces however these get stronger as you go down the group.

  Physical properties : low boiling and melting point, colourless, odourless, gas at room temp
• Group 1 - Alkali metals 


  All have 1 electron in their outer shell

  Low density metals

  Soft metals

  Have relatively low melting points

  Stored under oil to prevent them reacting with water or oxygen