C1:Atomic structure and the periodic table

C1:Atomic structure and the periodic table

1. Atoms

   • Radius of 0.1 nanometers
   • Nucleus
     • Protons - +1 charge. Relative mass of 1
     • Neutrons - 0 charge. Relative mass of 1
     • Overall positive charge
     • Almost all mass of atom
   • Electrons - -1 charge. Relative mass of negligible
   • No overall charge - equal amount of protons and electrons
   • atomic no. - no. of protons
   • mass no. - no. of protons and neutrons

2. isotopes

   • contains extra neutrons
   • same atomic number
   • different mass number

3. Compunds

   • held together by chemical bonds
   • chemical reaction needed for separation

4. mixtures

   • No chemical bond
   • Easily separated

5. Paper Chromatography

   • use pencil to draw line - insoluble (wont dissolve in solvent)
   • use lid - stops solvent from evapourating
   • solvent seeps up paper carrying the ink with it
   • take paper out and let dry when it nearly reaches top
   • ink should touch liquid to prevent dissolving

6. separation techniques

   • filtration - removes insoluble solids from liquids
   • evapouration - removes soluble solids from solution (formation of crystals)
   • distillation - removes soluble solids from solutions
   • filtration and crystallisation- separates rock salt (salt and sand)

7. history of the atom

   • 1) Dalton - solid spheres. different ones made up different elements
   • 3) Rutherford -Alpha particle scattering experiment. Nuclear model. mostly empty space, concentrated positive charge. Cloud of negative electrons
   • 4) Bohr - electrons contained in fixed shells. Electrons orbit nucleus. fixed distance from nucleus
   • 5) Chadwick - provided evidence for neutrons.
   • 2) JJ Thomson - Plum pudding. positive ball of charge with electrons stuck in it

8. Periodic table structure

   • Tried to organise through chemical properties
   • tried to organise using relative atomic mass
   • mendeleev
     • left gaps
     • predicted new elements
     • mainly in order atomic mass
     • properties of elements could be guessed using structure

9. Group 1

   • Reactive, soft metals
   • one electron in outer shell
   • More reactive as you go down
   • low melting and boiling points
   • vigorous reaction with water and chlorine gas, o2 and group 7
   • react with oxygen to make metal oxide

10. Group 7

    • non metals
    • Coloured vapours
    • less reactive as you go down
    • high melting and boiling point
    • form ionic bonds with metals
    • bond covalently too
    • will displace less reactive members of the group

11. Group 0

    • inert, colourless gases
    • boiling points increase as you go down
    • noble gases
    • dont react with much
    • full outer shell