1. Polarity Bonds and molecules

2. Types of bonds Ionic bonds occur when an atom of low ionisation energy loses valence electrons to an atom of high ionisation energy.

3. Types of bonds Covalent bonds occur when atoms of similar ionisation energies share valence electrons.

4. Types of bonds Ionisation energy is the energy required to remove loosely held valence electrons from an atom. A similar property is how well atoms attract or hold electrons when bonding.

5. Types of bonds The name given to this electron attracting ability of atoms is electronegativity.

6. Types of bonds

7. A very large difference in electronegativities between atoms in a bond will produce an ionic bond. A small difference produces a covalent bond.

8. Types of bonds If the atoms in a covalent bond have identical electronegativities then they will share the electrons equally.

9. Types of bonds Neither end of the bond will be more negative than the other. This symmetrical bond is known as a non-polar bond.

10. Types of bonds If two atoms bond with slightly different electronegativities then one atom will have an uneven share of the electrons.

11. Types of bonds This unsymmetrical bond will have one end which is more negative than the other due to the electrons spending more time there.

12. Types of bonds This bond is said to have a dipole since each end is different. It is called a polar bond. 

13. eg hydrogen fluoride

14. Types of molecules The previous examples of molecules were diatomic. There is only one bond in each. If the bond is polar then the molecule is polar.

15. Types of molecules If the bond is non polar then the molecule is also non-polar. eg Cl 2

16. Types of molecules If a molecule has more than one line of symmetry it will be non-polar.

17. Types of molecules eg BF 3, CCl 4, CO 2

18. Types of molecules If a molecule has only one line of symmetry it will be polar.

19. Types of molecules CHCl 3, NH 3, H 2 O

20. shape and polarity influence the chemical and physical properties

21. Types of molecules