1. Chemical Bonding 1. Covalent bonding 2. Ionic bonding All elements and atoms need stability.

2. Ionic Bonding This occurs when electrons are transferred. Reacting sodium (Na) with chlorine (Cl):

5. Ionic Bonding This occurs when electrons are transferred. Metal atoms lose the electron, or electrons, in their highest energy level and become positively charged ions. Non-metal atoms gain an electron, or electrons, from another atom to become negatively charged ions. The force of attraction between these oppositely charged particles keeps them together. This occurs between metals and non-metals.

6. Patterns Group 1+1Na+ Group 2+2Mg2+ Group 3+3Al + Group 4Share electrons Group 5-3N-3 Group 6-2O-2 Group 7-1Cl-3 Group 0Unreactive http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/atomic/ Group 1 elements react with elements in group 7. Group elements lose an electron and group 7 elements gain an electron.

7. Covalent bonding This occurs when electrons are shared. These occur between non-metals.

8. Example 1 Water

9. Example 2 Oxygen Oxygen Atom Oxygen Molecule (O 2) Oxygen Molecule (O 2)

10. Example 3 Chlorine

11. Use your periodic tables and knowledge of electron arrangements to answers the following questions: 1. Why are group 7 elements (halogens) so reactive? 2. Why are group 0 elements (noble gases) so un- reactive?

12. 3. Draw the ions that would be formed for the following: Aluminium (Al) Potassium (K) Fluorine (F) Oxygen (O) For each state whether electrons had been lost of gained.

13. 4. Complete the following table: Atomic number AtomElectronic structure of atom IonElectronic structure of ion 8O[2,8]2- 192,8,8,1K+ 17ClCl- 202,8,8,2 5. Draw dot and cross diagrams to show how the following to form ions together: - lithium and chlorine - calcium and oxygen - aluminium and chlorine

14. 6. Draw diagrams to show the covalent bonds between the following atoms: - 2 hydrogen atoms - 2 chlorine atoms - a hydrogen and a fluorine atom