c1- atomic structure/periodic table

• what are the sub particles in the nucleus. Give their charges and relative mass.


  Proton; +1 charge and relative mass=1

  neutron: no charge and rm=1
• what is the overall charge of an atom and why?


  are neutral (have no charge) as they have the same number of protons and electrons so cancel out
• What is an element 


  a substance made up of atoms with the same number of protons in their nucleus
• what is an isotope 


  different forms of the same element: contain the same number of protons but a different number of neutrons
• how big is an atom


  0.1nm (1x10^-10metres)
• how big is a nucleus?

  1x10^-14 metres

  (most is empty space)
• what charge is a nucleus


  positive (due to protons)
• where is most of the mass of at atom concentrated?

  the nucleus
• what is the relative mass and charge of a proton?


  Mass: 1 Charge: +1
• what is the relative mass and charge of a neutron?


  Mass: 1 Charge: 0
• what is the mass and charge of an electron?


  Mass: very small Charge: -1
• what is the charge of an atom and why?

  Neutral (no charge)

  they have the same number of protons and electrons
• what is an element?


  A substance made up of atoms that have the same number of protons in their nucleus
• what is an ion?


  An ion is an atom or molecule that has gained or lost electrons, resulting in a positive or negative charge.
• what is the mass number of an element?


  Sum of protons and neutrons
• what does isotope abundance mean?


  how common/rare the isotope is
• how do you calculate the RAM of an isotope?

  sum of (isotope abundance x isotope mass)

  /

  sum of abundance of all isotopes
• what is a molecule?


  2 or more atoms (non metals) held together by chemical bonds - e.g oxygen, chlorine, water

  (covalent bonding)
• what are compounds?


  2 or more different elements held together by chemical bonds
• why is sodium chloride not a molecule?

  it is an Ionic compound (consists of a metal)
• what is a mixture?


  two or more substances that are not chemically bonded.
• how can we separate mixtures?

  Filtration, distillation, chromatography.
• what does insoluble mean?


  Unable to be dissolved.
• in separation techniques what is a mixture?

  an insoluble solid in a liquid that has not dissolved

  e.g- sand in water
• what is a solution? 


  a liquid and a soluble solid

  eg salt in water
• what is a solute?


  a substance that is dissolved in a solvent to form a solution.
• what is a solvent?


  A substance that dissolves other substances.
• what does filtration do?


  separates insoluble solids from liquids using filter paper
• how does filter paper work?


  it has lots of tiny holes which can allow liquids to pass through but not solids
• how does filtration work?


  pour the solution into the filter funnel (lined with filter paper) and the solid should be left
• how would you separate a soluble solid in a liquid?

  Evaporation/crystalisation
• what are the steps of evaporation?


  1. place solution in evaporating dish- place it on a tripod and slowly heat it with a bunsen burner
  2. as the liquid starts to evaporate, crystals will start to form
• what are the benefits of evaporation?


  -quick and easy
• what are the negatives of evaporation?


  some solids may decompose

  (thermal decomposition)

  will be broken down into other things
• why is crystallisation used instead of evaporation?


  -is a slower technique for solids susceptible of thermal decomposition
• what are the steps of crystallisation?


  1. place the solution in an evaporation dish
  2. heat it gently in a water bath
  3. once some solvent has evaporated and crystals start to appear- stop heating it and leave it to cool
  4. as it cools more crystals start to form
  5. filter out the crystals from the remaining solution (using filter paper and funnel)
  6. dry the crystals by heating in an oven
• when is simple distillation used?


  To separate liquids from a solution
• what are the equipments needed in simple distillation?


  flask- containing the liquid mixture trying to separate

  the flask is sealed with a bung so that no gas can escape

  a thermometer is placed through the bung to measure the temperature in the flask

  condenser- main pipe surrounded by water jacket (containing a stream of continuously flowing cold water)- fed in at the bottom and out at the top

  beaker to capture the pure liquid

  and a bunsen burner to heat the solutions (under the flask)
• how does simple distillation work?


  1. heat up the mixture so that the liquid needed evaporates
  2. as it rises to the top of the flask, the pressure forces it down the condenser
  3. the vapour will cool and condense into liquid form
  4. which will run down the pipe and collect in the beaker
• when is fractional distillation used?


  Separating mixtures of liquids