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Elements and Compounds

Objective: Understand the periodic table and the difference between elements and compounds.
Assessment task: Assignment:
Length: 4 weeks (finish week 5 term 1).
Key questions
  • what is the smallest particle?
  • what happens to your body when you die?
  • What is the difference between an element and a compound?
  • How are ….
Key learning tasks.
  • Research one element and create a super hero character. Draw Lithium man, captain carbon.
  • Colour code elements (assignment sheet on wiki). Begin week 2.
  • Mini Prac - cereal with iron filings (demo)…
  • Metals and non-metals p47
  • Flame test p47… proper write up
  • Iron filings and sulfur. p54
  • Charged particles: Ionic compounds and copper plating are extension tasks.

1. Elements


Focus Questions
  • What is an element? What are the elements symbols?

    Make a new keynote and save it as Elements in your science folder.
    On the first slide, put the title elements and compounds
    On the second slide find a definition for an element. Give some examples of elements and put their symbols next to them.


  • How are elements discovered?

    On a new slide, give an example of how you might find out whether or not bread is an element. List the experimental steps you would take.
    bread.jpeg
    Look at this concept map prepared by a year 8 class. It breaks down bread into elements and compounds.
    Using XMIND create a digital concept map. Include pictures if you know how.
    Whilst making the concept map think of three questions you have about elements and compounds.
    Send these questions and your finished concept map to your teacher for grading.

DSC02015.jpg

Demo:
Sulfuric acid and sugar. What do you think will happen when we mix these two chemical compounds?

  • What is an atom and what are the three things which are in every atom?

    Make a labelled diagram of an atom in your keynote.
    Now do one for Hydrogen, Helium and Lithium
atoms.jpeg
  • Who was Mendeleev and what input did he have to chemistry?


    Make a page on your keynote about Meldeleev and give a quick history about him and describe his main contribution to science.
mendeleev.jpeg
What is the periodic table and how is it arranged

periodic.jpeg
  • Where are the metals, non-metals and metalloids located on the periodic table?

    Add a slide showing the metals, non-metals and mettaloids in the periodic table.

Links:
Dmitri Mendeleev - http://en.wikipedia.org/wiki/Dmitri_Mendeleev
Periodic table - http://www.ptable.com/ , http://www.webelements.com/

2. Metals and Non-metals - Investigation


You will be given a number of different substances and you need to decide whether or not they are metals or non-metals. Compile a laboratory report with your findings.

You will need:
  • Samples of metals and non-metals (as many as possible),
  • sandpaper, pliers,
  • power pack, connecting wires with crocodile clips,
  • 6 volt light bulb in a holder.

Make a new keynote and call it "Metals and Non-metals"
Use this keynote to make your lab report. Include as many pictures as you can of the experiments. You should also take a picture of each sample to put into your results table.

Aim: To investigate a number of different elements and determine which are metals and non-metals.

Materials: Record all the materials you are using here

Method:
1. Draw up a table to record the properties of the elements you are going to test. The properties you are going to be testing are: Lustre (is it shiny), Malleability (can it be bent or is it brittle?), Electrical conductivity (Does it conduct electricity?). Your table should look similar to the one below.

Sample
Lutsre
Malleable?
Electrical conductivity
Gold
Very shiny
Yes
Good conductor
Plastic
Very shiny
Can be bent but snaps if best too far
No electrical conductivity

2. Look at each sample. Is it shiny or dull? If the surface isn't shiny to start with, rub it with sand paper. Does anything change? Record the results in your table.

3. Try to bend each sample with your fingers and then with pliers if you need to. If it can be bent, it is malleable. If it breaks into pieces you can say it's brittle. Record the results in your table and take pictures.

4. To test electrical conductivity, set up a circuit as shown on the board and in the picture below. If the light globe light up then the sample conducts electricity. If the globe doesn't light up then the sample is a poor conductor.
conductivity.jpg
Questions:
1. Which of the samples are metals?
2. Is there any samples which were difficult to classify as being either a metal or a non-metal?
3. Design a more accurate test to determine electrical conductivity.
4. Research whether or not metals can be both brittle and malleable. How could you make a malleable metal brittle?



3. Compounds


4. Making compounds (prac))


Iron filings and Sulfur

Aim: To change a mixture of two elements into a compound.

Read the investigation carefully.
Describe to your partner what you have to do in part A.
Your partner will then describe what has to be done in Part B.
What other safety precautions will be necessary?
Discuss how you will dispose of leftover chemicals.
Design a data table in which to record your observations.
Apparatus:
Powdered Sulfur, Iron filings, Spatula, Bar magnet, 3 Small test tubes, Hydrochloric acid, Mortar and pestle,
Hand lens,
Method: Part A
1. Put a small amount of iron filings into a test tube. Use a hand lens to look closely at the iron filings. What happens when you
bring a magnet up to the side of the test tube?
Record your observations and inferences.
2. Add a small amount hydrochloric acid to the iron filings.
Record your observations and inferences.
3. Repeat steps 1 and 2 using sulfur instead of iron filings.
4. Mix two spatulas of sulfur with a spatula of iron filings in a test tube. Use a hand lens to examine the mixture.
5. Can you separate the iron filings from the sulfur using a magnet as in step 1?
6. Can you separate the iron filings and sulfur by adding some of the mixture to water? Try it.
Part B Making a Compound
Step 1 2 and 3 was pre done by the teacher.
4. Examine with a hand lens can you see any iron filings or bits of sulfur
Can you separate any iron using a magnet.
What happens when you add hydrochloric acid to some of the substance.
Can you separate any sulfur by adding some of the substance to water.

Results
1.Did the properties of the mixture of iron filings and sulfur change when you heated it? Explain
2.Did a chemical reaction occur. How do you know.

Conclusion
1.Use the results to explain the difference between a mixture and a compound.
2.The new substance you have made is called iron sulfide. What are the in it? Write a word equation to show how
it was formed


5. Atoms, Ions and Ionic Compounds


6. Electroplating using copper ions (prac)


Assessment Task:

Make a periodic table by hand (in groups of 2).
Include
  • all the information that you have learnt in the unit.
  • Your periodic table should be A3 and colourful.
  • It should be a bit like a concept map with the periodic table in the middle.
  • It should include an atomic structure diagram.
  • Clearly show the names and characteristics of the different groups of elements.
  • Include a definition of what an element and a compound is, with an example of each.

When you are finished they will be hung around the room for decoration and for bragging rights :).

An alternative and downloadable task...