Properties of Elements Pre-Lab: (Answer questions on your data sheet.) 1. Using a periodic table, determine and write the chemical symbol for each of the eight elements listed on your data sheet. 2. Predict whether each element is malleable or brittle and record your prediction in the data table. Safety Considerations: Always wear safety glasses in the chemistry lab. Never eat or drink in the chemistry lab. Hydrochloric acid solution is corrosive to eyes and skin. Cupric chloride solution is toxic if ingested. Avoid contact of all chemicals with eyes and all body tissues. Wash your hands before leaving the chemistry lab. Materials: Aluminum Tin Conductivity apparatus Carbon Zinc Forceps Copper 0.1 M CuCl 2 Periodic table Magnesium 1.0 M HCl 2 Waste containers Silicon Well plates Sulfur Well plate templates Procedure: 1. Obtain a well plate and a well plate template. You will go to different stations in the lab to obtain samples of each element and do physical and chemical tests. 2. Complete columns 1 and 2 on your data table as directed on the pre-lab. 3. Take the well plate to a station and place a small piece of each element in two separate wells. (NOTE: Do not touch any of the elements with your hands. Use forceps to obtain each sample.) Page 1 of 5
Sample Element Symbol Malleable or Brittle? (prediction) Malleable or Brittle? (demonstration) Color Luster Other Characteristics Conductivity HCl Test CuCl2 Test Pre-Lab: 1. Complete Column 1 (Element Symbol) in the data table below. 2. Complete Column 2 (Malleable or Brittle? Prediction) in the data table below. Data Table: Part 1- Physical Properties Chemical Properties Aluminum Carbon Copper Magnesium Silicon Sulfur Tin Zinc Page 2 of 5
Part 1 Physical Properties 4. Observe and record the color of the element in the Data Table. Is the sample silver, gray, colored, etc? Be very specific in recording observations. 5. Observe and record the luster of the element in the Data Table. Is the sample shiny, slightly shiny, pearly, dull, metallic? 6. Record any other physical properties that are observed about each element in the Data Table. Be specific in your observations. What form is the sample in? Is the sample crystalline, flaky, rough, smooth, flat and plate-like, rocky, in strips? Is there any odor or are any vapors given off? (Note: Avoid breathing any vapors directly. Instead of smelling a sample directly, waft the vapors from the sample toward your nose.) 7. Use the nail provided to determine whether your sample is malleable or brittle. Remove the sample from the well plate and place it on a piece of paper on the table. Press the sample firmly with the nail. If it bends, it is malleable. If it breaks, it is brittle. 8. Use the conductivity apparatus to test the conductivity of your sample. Turn the conductivity apparatus on. Touch both electrodes to the element being tested, being sure the electrodes are not touching each other. Scale Red LED Green LED Conductivity 0 Off Off Low or None 1 Dim Off Low 2 Medium Off Medium 3 Bright Dim High 4 Very Bright Medium Very high Part 2 Chemical Properties 9. a. Obtain a dropper bottle of 1 M HCl. Determine the reactivity of each sample with acid by adding 10 drops of HCl to one well of the sample. b. Obtain a dropper bottle of 0.1M CuCl 2. Determine the reactivity of each sample by adding 10 drops of CuCl 2 to the other well of the sample. c. Test your tin sample with either HCl or CuCl 2 as directed by your teacher. 10. Evidence for a chemical reaction may be the formation of gas bubbles and/or discoloration on the surface of the element. Observe and record results in the Data Table. Some reactions may be slow to start be patient. Allow samples about 5 minutes to react. You may continue testing the remaining elements while the samples react. 11. Repeat steps 1-9 with the other element samples found at the remaining stations. 12. Clean-up: Empty solutions and unreacted samples in a waste container provided by your teacher. Clean the well plate with water and a cotton swab, dry, and return to well plate box. Page 3 of 5
Questions: 1. Review the data gathered for the eight elements. Sort the eight elements into three groups, based on similarities and differences in their physical and chemical properties. Using this information plus information from your book, classify each group as metal, nonmetal, or metalloid. 2. Are there any inconsistencies within the groups you made? Do any elements seem to have properties of both groups? Which? Explain. 3. Look at the location on the periodic table of each of the eight elements tested in this lab. How do the properties of these elements compare to their general position on the periodic table? Make generalizations about the position of the metals, nonmetals, and metalloids on the periodic table. 4. Predict the physical and chemical properties of the following elements which were not tested in this lab selenium, calcium, and cobalt. Page 4 of 5
Elaboration Questions: 5. Given the melting point data below, create 3 general statements about the melting points of metals versus nonmetals. Are there any exceptions? Explain. Aluminum 660 0 C Carbon 3652 0 C Copper 1063 0 C Magnesium 649 0 C Silicon 1410 0 C Sulfur 113 0 C Tin 232 0 C Zinc 420 0 C Iodine 114 0 C Germanium 937 0 C Bromine 7 0 C 6. Research the everyday uses of the elements used in this lab. Use the internet or library and share your findings with the class. 7. Develop a process chart for testing elements not included in this experiment to determine whether the element is a metal, nonmetal, or metalloid. Page 5 of 5