1. Lattice Energy

2. Properties affected by bond strength melting/boiling point (stronger bonds = higher melting/boiling point)

3. Properties affected by bond strength melting/boiling point (stronger bonds = higher melting point/boiling point) hardness (stronger bonds = harder crystals)

4. Properties affected by bond strength melting/boiling point (stronger bonds = higher melting point/boiling point) hardness (stronger bonds = harder crystals) odor (stronger bonds = weaker odor)

5. Properties affected by bond strength melting/boiling point (stronger bonds = higher melting point/boiling point) hardness (stronger bonds = harder crystals) odor (stronger bonds = weaker odor) state at room temperature (stronger bonds are more likely to be solids)

6. Bond formation Whenever a new bond forms, energy is released. The stronger the bond, the more energy that is released.

7. Bond formation Whenever a new bond forms, energy is released. The stronger the bond, the more energy that is released. For ionic bonds, this energy is called lattice energy.

8. Bond formation Whenever a new bond forms, energy is released. The stronger the bond, the more energy that is released. For ionic bonds, this energy is called lattice energy. Higher lattice energy values correspond to stronger bonds.

9. Bond formation Whenever a new bond forms, energy is released. The stronger the bond, the more energy that is released. For ionic bonds, this energy is called lattice energy. Higher lattice energy values correspond to stronger bonds. The amount of energy released when a bond forms is identical to the amount of energy required to break the bond.

10. Predicting lattice energy Two factors will determine the lattice energy for ionic compounds.

11. Predicting lattice energy Two factors will determine the lattice energy for ionic compounds. – Bigger charges produce higher lattice energies (2+ and 2- produce stronger bonds than 1+ and 1-)

12. Predicting lattice energy Two factors will determine the lattice energy for ionic compounds. – Bigger charges produce higher lattice energies (2+ and 2- produce stronger bonds than 1+ and 1-) – Fewer energy levels result in greater lattice energies (LiF will have a greater lattice energy than NaCl)

13. Predicting lattice energy Two factors will determine the lattice energy for ionic compounds. – Bigger charges produce higher lattice energies (2+ and 2- produce stronger bonds than 1+ and 1-) – Fewer energy levels result in greater lattice energies (LiF will have a greater lattice energy than NaCl) – Charge is by far the bigger factor and should always be compared first!!!

14. Which compound will have the greatest lattice energy, MgS or LiF?

15. Magnitude of charge is the first thing we should look at.

16. Which compound will have the greatest lattice energy, MgS or LiF? Magnitude of charge is the first thing we should look at. – magnesium (2+ charge), sulfide (2- charge)

17. Which compound will have the greatest lattice energy, MgS or LiF? Magnitude of charge is the first thing we should look at. – magnesium (2+ charge), sulfide (2- charge) – lithium (1+ charge), fluoride (1- charge)

18. Which compound will have the greatest lattice energy, MgS or LiF? Magnitude of charge is the first thing we should look at. – magnesium (2+ charge), sulfide (2- charge) – lithium (1+ charge), fluoride (1- charge) – MgS has the greater individual charges, so MgS has the greater lattice energy.

19. Which compound will have a lower melting point, Na 2 S or BeO?

20. A lower melting point means we need to select the compound with the lower lattice energy. We check the charges first.

21. Which compound will have a lower melting point, Na 2 S or BeO? A lower melting point means we need to select the compound with the lower lattice energy. We check the charges first. – sodium (1+), sulfide (2-)

22. Which compound will have a lower melting point, Na 2 S or BeO? A lower melting point means we need to select the compound with the lower lattice energy. We check the charges first. – sodium (1+), sulfide (2-) – beryllium (2+), oxide (2-)

23. Which compound will have a lower melting point, Na 2 S or BeO? A lower melting point means we need to select the compound with the lower lattice energy. We check the charges first. – sodium (1+), sulfide (2-) – beryllium (2+), oxide (2-) – sodium sulfide has smaller individual charges, so it has the lower melting point.

24. Which compound has harder crystals, CaCl 2 or MgCl 2 ?

25. Harder crystals require a higher lattice energy. First, check the charges.

26. Which compound has harder crystals, CaCl 2 or MgCl 2 ? Harder crystals require a higher lattice energy. First, check the charges. – calcium (2+), chloride (1-)

27. Which compound has harder crystals, CaCl 2 or MgCl 2 ? Harder crystals require a higher lattice energy. First, check the charges. – calcium (2+), chloride (1-) – magnesium (2+), chloride (1-)

28. Which compound has harder crystals, CaCl 2 or MgCl 2 ? Harder crystals require a higher lattice energy. First, check the charges. – calcium (2+), chloride (1-) – magnesium (2+), chloride (1-) – the charges are the same, so we need to see which ions have fewer energy levels.

29. Which compound has harder crystals, CaCl 2 or MgCl 2 ? – the charges are the same, so we need to see which ions have fewer energy levels. – calcium (4), chloride (3)

30. Which compound has harder crystals, CaCl 2 or MgCl 2 ? – the charges are the same, so we need to see which ions have fewer energy levels. – calcium (4), chloride (3) – magnesium (3), chloride (3)

31. Which compound has harder crystals, CaCl 2 or MgCl 2 ? – the charges are the same, so we need to see which ions have fewer energy levels. – calcium (4), chloride (3) – magnesium (3), chloride (3) – fewer energy levels give MgCl 2 the higher lattice energy and therefore, the harder crystals.

32. Which compound has the lower boiling point, AgNO 3 or K 2 SO 4 ?

33. Lower boiling point means a lower lattice energy.

34. Which compound has the lower boiling point, AgNO 3 or K 2 SO 4 ? Lower boiling point means a lower lattice energy. – silver (1+), nitrate (1-)

35. Which compound has the lower boiling point, AgNO 3 or K 2 SO 4 ? Lower boiling point means a lower lattice energy. – silver (1+), nitrate (1-) – potassium (1+), sulfate (2-)

36. Which compound has the lower boiling point, AgNO 3 or K 2 SO 4 ? Lower boiling point means a lower lattice energy. – silver (1+), nitrate (1-) – potassium (1+), sulfate (2-) – Charges indicate a lower lattice energy for AgNO 3. Lower lattice energy means a lower boiling point.