1. Prepare and Observe Two Forms of Iron Ions

Name Class Date

Lab – s Before d

Objectives

1. Prepare and observe two forms of iron ions.

2. Given the charge of each ion, determine the electron configuration.

3. Investigate the relationship between the electron configuration and ionic charge of other elements.

Materials

2 test tubes test tube rack

stopper 10-mL graduated cylinder

iron filings 6 M hydrochloric acid (HCl)

iron (III) chloride (ferric chloride, FeCl3) metal spatula

deionized water

Procedure

1.  Into a test tube, place 2 metal spatulas of iron filings (or a marble sized ball of compressed steel wool). Use the graduated cylinder to add 2.0 mL deionized water to the test tube. Use the graduated cylinder to add 4.0 mL 6 M HCl. Caution: Always add to acid to water. Hydrochloric acid causes chemical burns. Avoid skin contact. Neutralize spills with sodium hydrogen carbonate (baking soda) before wiping up with a paper towel. Holding the top of the tube, tap the lower part with your finger to mix. Return the tube to the rack.

2.  Into the second test tube, place a small pea-sized piece of iron (III) chloride, FeCl3. Add 6.0 mL deionized water to the test tube. Place a stopper in the test tube and shake until some of the compound has dissolved. Record your observations of both test tubes in the data table below. (The processes may take a couple minutes.)

3.  Decant liquids carefully down the drain with water running in the sink. Dispose of solids in the container provided. Wash the equipment used with soap. Rinse with tap water. Finally, rinse with deionized water and invert to dry.

Observations

Observations
Test tube 1
Test tube 2

Conclusions

1.  Write the electron configuration for an iron atom.

...for an iron ion with 2+ charge

...for an iron ion with 3+ charge

2.  Which two electrons are lost to form the pale green Fe2+ ion?

3.  Which additional electron is lost to form the yellow Fe3+ ion?

4.  (1) Write the electron configuration for atoms of each of the following elements. (2) Circle the valence electrons in each electron configuration. (3) Predict the most likely ionic charge.
Hint: Atoms tend to lose, gain or share electrons to get the electron configuration of a noble gas.

a.  sodium Predicted ionic charge

b.  calcium Predicted ionic charge

c.  sulfur Predicted ionic charge

d.  phosphorus Predicted ionic charge

e.  aluminum Predicted ionic charge

f.  krypton Predicted ionic charge

5.  Was the making of the green Fe2+ ion from iron metal and hydrochloric acid a physical or chemical change? Why?

6.  Was the preparation of the yellow Fe3+ ion from the iron (III) chloride solid a physical or chemical change? Why?