Atomic Structure

Atomic Structure

1. Nuclear model

   • Small nucleus surrounded by electrons
   • Protons and neutrons have the same mass
   • The number of protons always equals the number of electrons

2. Elements consist of one type of atom only

   • 100 different elements

3. Periodic table

   • Vertical collumns are groups
   • Elements in the same group have the same number of electrons in their outer shell
     • Group 0 are the nobel gases
       • Stable and unreactive because they have 8 electrons in their outer shell

4. Atomic mass

   • Top is the mass number
     • This is the total number of protons and neutrons
   • Bottom is the atomic number
     • The number of protons (so also the number of electrons)

5. Isotopes

   • The same except for a few extra neutrons
     • Different atomic forms of the same element
   • Same atomic number but different mass number
   • Eg Carbon 12 and Carbon 14

6. Electron shells

   • 2,8,8,8,....
   • Want them full
   • Use the periodic table to work out what structure each element has

7. Compounds

   • Different elements react to make compounds
   • Metal to metal consists of Ions
     • metal loses: non metal gains
       • Ionic bonding
   • Non metals is molecules
     • Share = covalents