C3 Part 1 - The Periodic Table

PERIODIC TABLE
1. The periodic table
  1. Atomic Number
    1. The number of protons in an atom of an element
  2. Elements arranged in order of increasing atomic number
2. Alkali metals - 1
  1. The more easily the outer electron is lost, the more reactive the Group 1 element is
    1. As you go down Group 1, electronic shielding increases - this means the "pull" on the outer electron from the nucleus is reduced
      1. The outer electron is also further away from the positive nucleus as you go down the Group
  2. Density
    1. Density (gcm-3) = Mass(g)/Volume(cm3)
      1. Lithium - 0.53gcm-3
      2. Sodium - 0.97gcm-3
      3. Potassium - 0.86gcm-3
      4. Rubidium - 1.53gcm-3
      5. Lithium, Sodium and Potassium will all float on water as their density is less than water (1gcm-3)
  3. Low densities
  4. Soft
  5. Low melting and boiling point
    1. As you go down Group 1 metals, the melting and boiling point of the alkali metals decrease
      1. Melting point
        Lithium - 180
        Sodium - 97.8
        Potassium - 63.5
        Rubidium - 38.9
        Caesium - 28.7
        Francium - 27
      2. Boiling point
        Lithium - 1330
        Sodium - 890
        Potassium - 774
        Rubidium - 688
        Caesium - 690
        Francium - 680
3. Alkali metals - 2
  1. Alkali metals reacting with air (oxygen)
    1. Sodium + Oxygen --> Sodium Oxide
      1. 4Na+ + O2- > 2Na2O
  2. Alkali metals reacting with halogens to form Alkali metal Halides
    1. Sodium + Chlorine --> Sodium Chloride
      1. 2Na + Cl2 --> 2NaCl
  3. Alkali Metals and water
    1. Sodium + Water --> Sodium Hydroxide + Hydrogen
      1. 2Na + 2H2O --> 2NaOH + H2
4. The Transition Elements
  1. Centre block of Periodic table
  2. High Densities, Hard, Strong
  3. Do not react vigorously with water
  4. Frequently used as catalysts
5. The Halogens
  1. As you go up Group 7, the reactivity increases
  2. Diatomic molecules formed (F2/Cl2/Br2/I2)
  3. Weak intermolecular bonds between the diatomic molecules
    1. Low Melting point
    2. Low Boiling point
  4. As you go down Group 7 the melting and boiling point increase due to the intermolecular bonding between the molecules become stronger as you go down Group 7
  5. Iron + Chlorine --> Iron Chloride
  6. Colour
    1. Fluorine - Pale Yellow
    2. Chlorine - Pale Green
    3. Bromine - Orange/Brown
    4. Iodine - Purple Vapour
6. Organising the Elements
  1. Antoine Lavaiser
    1. Book
      1. Lists 33 elements
      2. Classifying them into gases, metals, non-metals and earths
  2. Stanislac Connizzaro
    1. Worked out
      1. Atomic weights and listed them in a scientific paper
  3. John Newlands
    1. 'Law of Octaves'
      1. Listed 56 elements in order of increasing atomic weight
        Every eighth element had similar properties
  4. Dmitri Mendeleev
    1. Published first periodic table
      1. Elements in order of atomic weights
      2. In groups of similar properties
      3. Predicted the elements that hadn't been discovered yet
  5. Johann Dobreiner
    1. Announced findings
      1. Elements come in groups of three
        Middle weight was and average of the lighter and heavier elements
  6. Alexandre Chancourtois
    1. Discovered
      1. Elements with similar properties occur at regular intervals
  7. Lothar Meyer
    1. Graph
      1. Volume of atom against atomic weight
        Noticed a pattern and deduced a periodic table

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