C2: Chemical Patterns

C2: Chemical Patterns

1. History of the Atom

   • John Dalton
     • Described atoms as solid spheres.
   • JJ Thomson
     • 1904 - Concluded that atoms weren't solid spheres. His measurements of charge and mass showed that it must contain electrons. His theory was the 'plum pudding model'. It showed the atom as a ball of positive charges with electrons in it.
   • Ernest Rutherford
     • 1911 - The experiment he carried out involved gold foil and alpha particles. He discovered the nucleus which was surrounded by electrons and that the atom was mostly empty space.
   • Niels Bohr
     • Discovered the electrons would be attracted to the nucleus, causing the atom to collapse, suggesting that all the electrons were contained in shells.

2. The Atom

   • Protons
     • Positively charged
   • Neutrons
     • No charge
   • Electrons
     • Negatively charged

3. Group 1 Elements

   • All have one electron in the outer shell - very reactive.
   • As you go down Group 1: Increasing reactivity, lower melting/boiling points and higher density.

4. Group 0 Elements

   • Knows as the noble gases
   • All have a full outer shell (apart from helium), so they don't have to lose/gain an electron
   • This includes:

5. Ionic Bonding

   • Simple ions form when atoms lose/gain an electron.
   • Can predict the ions formed by elements in Groups 1&2 and 6&7
   • It means the transfer of electrons

6. Ionic Compounds

   • Can be shown using the Dot and Cross Diagram
   • Have similar properties:
     • High melting/boiling points
     • Solid ionic compounds don't conduct electricity - ions are fixed in place
     • Dissolves easilty

Bilder und Dateien der Mindmap