1. Ionic and Covalent Compounds…
Write down the Electronic Configurations and Box Notations for: Ca
Mg2+ Cu
V(IV)
CO2

2. Ionic Compounds…
An IONIC BOND is the electrostatic attraction between a positive and negative ion that is formed by the transfer of (at least) one electron from the metal to the non-metal.

3. (complex ions are the only exception)
Ionic Compounds…
Metals are ALWAYS positive
Non-metals are ALWAYS negative
(complex ions are the only exception)

4. Ionic Compounds…
Dot and Cross diagrams show where electrons have been transferred to and from. They obey the following guidelines:
Use square brackets
Only show the outer shell of e-
The charge must be shown

5. Ionic Compounds…
Potassium metal forming an ion + K K

6. Cl Cl Ionic Compounds… Chlorine forming an ion - x x x x x x x x x x x

7. K K Cl Cl Potassium reacting with Chlorine + - x x x x x x x x x x x x

8. Ionic Lattices… Ionic compounds form lattices where:
Each +ve ion is surrounded by –ve ions
Each –ve ion is surrounded by +ve ions
Electrostatic attractions are experienced from all angles
You can calculate the number of ions from the mass of the crystal

9. Ionic Lattices…

10. Ionic Lattices…
All lattices have the following properties:
High melting/boiling point
Electrical conductivity
Solubility
In pairs, explain why.

11. Melting/Boiling Points
Ionic Lattices…
Melting/Boiling Points
There are STRONG ELECTROSTATIC bonds between each ion
These require HIGH amounts of ENERGY to break
This energy is provided in the form of HIGH TEMPERATURES

12. Ionic Lattices…
Melting/Boiling Points
The larger the charge of the ions the higher the melting point of the compound.
e.g. NaCl: mp = oC
MgO: mp = 2,852oC

13. Melting/Boiling Points
Ionic Lattices…
Melting/Boiling Points
If there is a difference in size of the ions the melting point decreases
e.g. MgO: mp = 2,852oC
SrO: mp = 2,531oC
BaO: mp = 1,923oC

14. Ionic Lattices… Conductivity
Solids DO NOT conduct electricity as the ions are in fixed positions.
Liquids/solutions DO conduct electricity as the ions can MOVE and CARRY CHARGE

15. Ionic Lattices… Solubility
Ionic solids will only dissolve in POLAR solvents.
Water molecules have polar bonds
The water molecules are attracted to the charged ions and break down the lattice
They surround each ion causing it to dissolve

16. Ionic Lattices…
Solubility

17. Identifying Compounds…
We’ve already learned how to identify the metal cation in a compound. Now we need to look at the tests for:
Non-metal cations
Anions

18. Identifying Compounds…
Ammonium
Add NaOH and warm gently
Place red litmus paper into the gas
Positive Result:
Red litmus turns blue
Equation:
NH4+(aq) + OH-(aq)  NH3(aq) + H2O(l)

19. Identifying Compounds…
When identifying compounds we must perform the tests in a specific order.
Carbonates
Sulphates
Halides

20. Identifying Compounds… Carbonates Add a dilute strong acid
Test any gas evolved with limewater
Positive Result:
Fizzing then limewater goes cloudy
Equation:
CO32-(aq) + 2H+(aq)  CO2(g) + H2O(l)

21. Identifying Compounds… Sulphates Add a dilute hydrochloric acid
Add aqueous BaCl2
Positive Result:
White Precipitate formed
Equation:
SO42-(aq) + Ba2+(aq)  BaSO4(s)

22. Identifying Compounds… Halides Dissolve in water
Add aqueous silver nitrate
Positive Result:
Precipitate formed
Equation:
Ag+(aq) + X-(aq)  AgX(s)

23. Identifying Compounds…
Halides
To determine the identity of the halide we first look at the colour:
White ppt = Chloride
Cream ppt = Bromide
Yellow ppt = Iodide

24. Identifying Compounds… Halides
If we cannot tell the colour (happens often) we add the ammonia
Dissolves in dilute= Chloride
Dissolved in conc = Bromide
Insoluble = Iodide

25. Covalent Compounds…
A COVALENT BOND is a shared pair of electrons that are electrostatically attracted to the positive nuclei of both atoms taking part in the bond.

26. Covalent Compounds…
Dot and Cross diagrams show where electrons have been transferred to and from. They obey the following guidelines:
No square brackets
Only show the outer shell of e-
Pair of electrons must be clearly shown

27. Covalent Compounds…
Bromine Br x x Br Br x x x x x x x Br x x x x x

28. Covalent Compounds…
DATIVE bonds are formed when the Octet Rule is not satisfied.
They often lead to a charged compound such as ammonium.

29. Covalent Compounds…
Ammonium + H H N H x x x H

30. Covalent Compounds…
Ammonium + H H N H H

31. The LARGER the value the STRONGER the bond
Covalent Compounds…
Bond Strength
Bond strengths are given as positive values because breaking bonds is an ENDOTHERMIC process.
The LARGER the value the STRONGER the bond

32. Covalent Compounds…
The Octet Rule is useful for the most part but there are certain elements that can be satisfied with less/more than eight electrons in their largest Quantum Number.

33. 2 3 5 3, 5 6 2, 4, 6 7 1, 3, 5, 7 Covalent Compounds… Group Elements
Potential maximum number of bonds 2 Be 3 B 5
P, As
3, 5 6
S, Se, Te
2, 4, 6 7
Cl, Br, I, At
1, 3, 5, 7

34. F B F F Covalent Compounds… Boron trifluoride x x x x x x x x x x x x

35. F F P F F F Covalent Compounds… Phosphorus pentafluoride x x x x x x x

36. Covalent Compounds…
Simple Molecules
Strong covalent bonds form between atoms
Weak intermolecular forces between molecules
Limited number of atoms

37. Covalent Compounds…
Giant Lattice
Strong covalent bonds between all atoms
No intermolecular forces to consider (except Graphite)
Potentially infinite number of atoms

38. Covalent Compounds… Properties CO2, CH4, HCl Low No Property
Simple Molecular
Giant Lattice
Example Compounds
CO2, CH4, HCl
Graphite, Diamond, SiO2
Melting/Boiling Point
Low
High
Electrical Conductivity No
No (except Graphite)
Solubility
In non-polar solvents due to the formation of London Forces
No – the bonds are too strong to be broken

39. Covalent Compounds…
Graphite forms layers of carbon atoms bonded to 3 other carbons.
Intermolecular forces hold the layers together.
One of the valence electrons is not involved in bonding.
Therefore it is free to move (delocalised) and carry a charge.