c1 atomic structure

• What is an atom

  Smallest part of an element. represented by a chemical symbol
• What is the law of conversation of mass

  The law of conservation of mass says that no atoms are lost or made during a chemical reaction.
• what is a compound

  A pure substance made from more than one type of element chemically bonded together
• what is a mixture

  A mixture consists of two or more elements or compounds not chemically joined together.
• what are 4 separating techniques

  • crystallization
  • filtration
  • fractional distillation
  • chromatography
• what is Crystallisation

  This is a separation technique to separate a soluble substance from a solvent. For example it can be used to separate salt from water or other substances that have dissolved.
• how to do crystallisation

  It involves adding the solution to an evaporating dish and heating it with a Bunsen Burner to get the water to evaporate. Heating is stopped when crystals form and the rest of the water is left to then evaporate at room temperature.
• what is filtration

  This is a separation technique to separate an insoluble substance from a solvent.
• how to do filtration

  It involves a funnel and filter paper and pouring the solution through the filter paper. The insoluble substance collects on the filter paper and this can then be washed and dried.
• What is Fractional distillation

  This is a separation technique to separate mixture of miscible liquids such as ethanol and water that have different boiling points.
• How to do fractional distillation

  nvolves adding the mixture to round bottom flask connected fractioning column that usually contains glass beads. This is then fitted to a condenser. The mixture is then heated with a Bunsen Burner to get the liquids to evaporate.
• what is chromatography

  a separation technique to separate different soluble substances from each other. It can be used to separate food colourings.
• how to do chromatography

  involves getting a piece of chromatography paper and drawing an origin line in pencil. A spot of the substance to be separated is then added to this origin line and the paper is then place in a solvent with the origin line above the solvent
• development of the atom-plum pudding model

  JJ Thomson suggested that the atom consisted of positive 'dough' with a lot of negative electrons stuck in it. 
• development of atom after thomsom

  Niels Bohr then adapted this model by suggesting that electrons orbit the nucleus at specific distances and then James Chadwick proved the existence of neutrons.
• structure of atom

  The atom has protons and neutrons in its nucleus with electrons orbiting in shells on the outside
• charge and mass of protons/neutrons/electrons

  protons- +1 / 1 mass

  neutrons- neutral / 1 mass

  electrons- -1 / very small mass
• Mass number

  sum of protons and neutrons in a atom
• Atomic number

  number of protons it has
• What is an ion

  An atom that has lost or gained electrons so has a charge
• What is an isotope

  Atoms with the same number of protons but different number of neutrons. They have different mass numbers
• What is a chemical reaction

  Reactants are what go into a chemical reaction while products are what are made
• How many electrons can each shell hold

  1st shell 2

  Every other 8
• What are the state symbols

  • Solid [s]
  • Liquid [l]
  • Gas [g]
  • Solution [aq]
• What is an element

  Elements are made up of just one type of atom