Accelerated Chemistry
Properties of Ionic Compounds Webquest Name:
You will now explore some common properties that ionic compounds have and why those properties exist.
Property #1: Ionic Compounds are Hard & Brittle
Ionic compounds have similar characteristics. They are all hard and brittle.
1.) Look up the following ionic compound images on Wikipedia.
Potassium iodide - http://en.wikipedia.org/wiki/File:Potassium_iodide.jpg
Calcium fluoride - http://en.wikipedia.org/wiki/File:Calcium_fluoride.jpg
Aluminum chloride - http://en.wikipedia.org/wiki/File:Aluminium-trichloride-hexahydratewhite-and-yellow.jpg
Calcium nitrate – http://upload.wikimedia.org/wikipedia/commons/1/14/Dusi%C4%8Dnan_v%C3%A1pena t%C3%BD.JPG
2.) What physical properties do all these compounds have in common with each other?
What common substance do these materials remind you of? Why do you think these compounds look similar to each other?
3.) Click on the following link - http://en.wikipedia.org/wiki/File:Halit-Kristalle.jpg
. It is a close-up of what salt (sodium chloride) looks like. Describe what you see.
4.) If you were to smash salt with a hammer, what do you think would happen? Describe what you might see (don’t just say it will break—tell HOW it might break)
5.) Why do you think ionic compounds are so hard and brittle (break easily)? Go to this website http://misterguch.brinkster.net/ionic.html
and go to the section “ionic compounds are very hard and very brittle.” Read the answer the author gives for why ionic compounds have these characteristics. Summarize the author’s answer below in your own words.

Accelerated Chemistry
Properties of Ionic Compounds Webquest Name:
Property #2: Ionic Compounds are Crystals
A crystal or a crystalline solid is a solid material made up atoms, molecules or ions that are arranged in an orderly, repeating pattern that extends in a 3D direction. Ionic compounds all have a crystalline shape.
Go to the following website to see what a crystalline structure looks like. http://en.wikibooks.org/wiki/High_School_Earth_Science/What_are_Minerals%3F#media viewer/File:Salt-cristalls.jpg
Draw what sodium chloride (NaCl) looks like under the microscope:
Property #3: The Melting Points of Ionic Compounds
One way to identify a material is to see what its melting point is. Every material has a unique melting point. For example, the melting point of ice is always 0 degrees Celsius or the melting point of mercury is 234 Kelvin.
Ionic bonds or the bonds between ionic compounds are the strongest type of bond between atoms that you can have. As a result of the really strong bond between ions, the melting point of materials is affected.
Look up the melting points for the following compounds by googling the compound and its melting point (should be the first thing that comes up on google):
Ionic Compounds
Sodium Chloride (NaCl)
Zinc Sulfide (ZnS)
Iron (III) Chloride (FeCl
3
)
Calcium Nitrate (Ca(NO
3
)
2
)
Iron (II) Sulfide (FeS)
Melting Points (degrees
Celsius)
Non-Ionic Compounds
(Covalent Compounds)
Water (H
2
O)
Ammonia (NH
3
)
Methane (CH
4
)
Carbon Monoxide (CO)
Carbon Tetrafluoride (CF
4
)
Melting Points (degrees
Celsius)
What do you notice about the melting points of ionic compounds versus the melting points of non-ionic compounds?
Why do you think the melting points of ionic compounds are different from the non-ionic compounds? HINT: think about the strengths of bonds between atoms! (HINT: when you melting something, you are breaking the bonds between atoms. Another reminder- ionic bonds are stronger than nonionic bonds…)

Accelerated Chemistry
Properties of Ionic Compounds Webquest Name:
Property #4: Ionic Compounds Dissolve in Water
A solution is a mixture of a solvent and solute. When an ionic compound is put into water, it dissolves and creates a solution. Because ionic compounds are able to break apart and dissolve in water, we call them soluble.
The picture above shows how an ionic compound, like NaCl is able to dissolve in water.
1.) When an ionic compound like NaCl, for example, is put into water, it breaks apart into positive and negative ions. What ions would NaCl break apart into?
2.) In water, what will the Na+ ions be attracted? (Look carefully at the picture)
3.) In water, what will the Cl- ions be attracted to? (Look carefully at the picture)
4.) Now watch this youtube video called “How does salt dissolve in water?” Write a summary of what you see happening. http://www.youtube.com/watch?v=dr4sFNzUVzI&feature=fvsr
5.) Watch the video called “Dissociation of NaCl on my website. Write a summary of what you see happening.

Accelerated Chemistry
Properties of Ionic Compounds Webquest Name:
Property #5: Ionic Compounds Conduct Electricity in Water
Since ionic compounds dissolve in water, the positive and negative ions simply wander all over the water. Electricity , by definition, is simply the movement of electrons through a material. In our house, electricity or electrons flow through wires.
Since ionic compound are positive and negative ions that separate and flow in water, it is easy to allow electrons to move around and create electricity.
1. Look at Picture A below. Distilled water is pure water- it is water that does not have anything dissolved in it. Why doesn’t distilled water conduct electricity?
2. Look at Picture B below , which is a picture of salt in solid form. Why doesn’t salt as a solid conduct electricity?
3. Look at Picture C below, which is salt dissolved in water. Why does salt dissolve in water conduct electricity?

Accelerated Chemistry
Properties of Ionic Compounds Webquest Name:
Homework- Reflection on Ionic Compounds
1.) Explain how ionic bonding works.
2.) What common physical properties do ionic compounds have? Why are they like this?
3.) What do ionic compounds have in common in regards to their melting points? Why are all there melting points like this? (Hint- has to do with their ionic bonds).
4.) What happens when you put ionic compounds in water?
5.) Why do ionic compounds in water conduct electricity?