1. Atomic structure and bonding
You must revise:
The structure of the atom
Electron arrangement
Ionic bonding
Covalent bonding
Metallic bonding

2. The structure of the atom
Central nucleus made up of positive protons and neutral neutrons. Negative electrons in shells around nucleus.

3. Protons, neutrons or electrons?

4. Electron arrangement 1st Shell: 2 electrons 2nd Shell: 8 electrons
3rd Shell: 8 electrons
Electrons are arranged in energy levels or shells around the nucleus.
The 1st shell holds a maximum of 2 electrons.
The 2nd and 3rd shells each hold a maximum of 8 electrons.
A magnesium atom has 12 electrons which can be written as: 2,8,2.
An argon atom has 18 electron which can be written as: 2,8,8.

5. Ionic Bonding: Bonding between metal and non metal atoms
Ionic bonding involves the transfer of electrons from the outer shell to form ions (charged particles)
Metals atoms lose electrons and form positive ions (e.g. Na+ sodium ion)
Non metal atoms gain electrons and form negative ions (Cl- chloride ion)

6. Covalent Bonding: Bonding between non-metal atoms
Covalent Bonding involves the sharing of pairs of electrons in the outer shells
The bonds between atoms are strong (Intra-molecular)
The bonds between molecules are weak causing low melting and low boiling points (Inter-molecular)

7. Metallic Bonding: Bonding in metals
Metals have giant structures of atoms which
are arranged in a regular pattern
Metals can be bent and shaped because their atoms
are arranged in layers which can slide over each other
Metals can conduct heat and electricity because of their
delocalised electrons which are free to move and carry the
current