Properties of Ionic Bonds

1. Properties of Ionic Bonds What are the characteristic properties of ionic bonds? A Virtual Lab Click Here to Continue

2. Properties of Ionic Compounds • Ionic compounds have unique properties, different from other compounds. We will be doing a virtual experiment in order to summarize these properties. • Goals: • Know and recognize an ionic compound based on its properties. • Explain why ionic compounds have the properties they have, by considering their physical and chemical structure. Click Here to Continue

3. Properties of Ionic Compounds • During this experiment we will consider: • Physical Appearance (questions 1-3) • Melting Point (questions 4-7) • Conductivity (as a solid, in water, and molten) (questions 7-8) • Solubility (in water, a polar solvent, and cyclohexane, a non-polar solvent) (questions 9-11) Click on the links above to perform each experiment.

4. Physical Appearance Below are three difference ionic compounds. Examine them. Fluorite (CaF2) Hematite (Fe2O3) Barite (BaSO4) Write down the things they have in common. All three have facets, or flat faces. Click Here to Continue

5. Physical Appearance Lets zoom in on a crystal of sodium chloride. Most ionic compounds are crystalline solids at room temperature. Why do they look like this?

6. Physical Appearance Why do they look like this? The best way to stabilize a positive charge is to surround it with negative charges, and vice versa for negative charges. This forms a neat “lattice” structure, giving the ionic crystals their facets. Click Here to Continue

7. Physical Appearance Each different shaped crystal has its own lattice structure. Fluorite (CaF2) Hematite (Fe2O3) Barite (BaSO4) Click Here to Continue

8. Properties of Ionic Compounds • During this experiment we will consider: • Physical Appearance (questions 1-3) • Melting Point (questions 4-7) • Conductivity (as a solid, in water, and molten) (questions 8-9) • Solubility (in water, a polar solvent, and cyclohexane, a non-polar solvent) (questions 10-12) Click on the links above to perform each experiment.

9. Melting Point C Several solids were placed on a plate, which is hanging over a Bunsen burner. B D You are going to record to order in which the solids melt. E A Click the Bunsen burner to turn on the flame – then wait and observe. Click Here to Continue

10. Melting Point First, determine which compound belongs to which letter by comparing the melting points to the melting order. Next, determine which compounds are ionic. If you are unsure how to do this, check your notes from last class or HW 2. Then write the name of the compound if it is ionic Compare the melting points off all the ionic compounds. Write a statement which summarizes the melting points of ionic compounds. Click Here to Continue

11. Melting Point • Why do ionic compounds have high melting points? The ions of an ionic compound are arranged in a very stable, neat, lattice structure. Oppositely charged ions are also very strongly attracted to each other. These add up, making ionic bonds very strong. This strength means it takes a lot of energy (heat) to break these bonds and melt the solid. Click Here to Continue

12. Properties of Ionic Compounds • During this experiment we will consider: • Physical Appearance (questions 1-3) • Melting Point (questions 4-7) • Conductivity (as a solid, in water, and molten) (questions 8-9) • Solubility (in water, a polar solvent, and cyclohexane, a non-polar solvent) (questions 10-12) Click on the links above to perform each experiment.

13. Conductivity • We will use a conductivity meter to test how well salt can conduct electricity. • We will test salt in three ways: • As a solid • Dissolved in water • Molten (melted into a liquid) Click Here to Continue

14. Conductivity Molten NaCl Solid NaCl We need to heat the solid salt to melt it. Click the Bunsen burner to turn it on. Lights Turn On! Solid NaCl No Lights! Pure Water Water with Salt We are going to test each of the following. Record if the lights appear for each in a table. Now we will add salt No Lights! The salt dissolves: NaCl  Na+1 + Cl-1 Click Here to Continue Lights Turn On!

15. Conductivity • Ionic compounds can only conduct electricity when the ions are able to move freely. • This does not occur in the solid, because the ions are trapped in the crystal lattice structure. • Pure water does not conduct. It has no ions! • When you added the salt to the water, the salt dissolved, freeing the ions from the lattice structure. Now the ions can move, and conduct electricity. • When the salt is melted (molten), the ions are free from the lattice structure, able to move. Thus they can conduct. Click Here to Continue

16. Properties of Ionic Compounds • During this experiment we will consider: • Physical Appearance (questions 1-3) • Melting Point (questions 4-7) • Conductivity (as a solid, in water, and molten) (questions 8-9) • Solubility (in water, a polar solvent, and cyclohexane, a non-polar solvent) (questions 10-12) Click on the links above to perform each experiment.

17. Solubility Solute (Salt) • Refers to how much of a given substance or compound will dissolve in a given amount of solvent. • Solute: Thing that gets dissolved. • Solvent: Thing that does the dissolving. Solvent (Water) Click Here to Continue

18. Solubility Click each beaker to add salt. Cyclohexane Nonpolar Water Polar Na+1 Cl-1 Record which solvent the salt was able to dissolve in. Click Here to Continue

19. Why are Polar Solvents able to Dissolve Ionic Compounds? • Click here to watch the video. • Polar solvents have charged ends, like water molecules. • These charges are able to rip apart ionic compounds by pulling apart the charges of the ions. Click Here to Continue

20. In Conclusion (Question 11) • Write a paragraph (minimum 8 sentences) that summarizes and explains the properties of ionic compounds. • You should use the following words: lattice structure, metal, nonmetal, ion, facet, energy. • You can click here to review any of the properties.