Comparing Chemical Properties Within a Group

Comparing Chemical Properties Within a Group Physical Science Lab –5.2 Name: Background Information: See class set paper.

Question: How does Reactivity vary among the alkaline Earth Metals?

Pre-Lab Questions. Read the entire lab before trying to answer the following: 1. Controlling Variables: Why is it important not to mix the test solution in one well with the solution in another well on your spot plate?

2. Designing Experiments: Why is the order of the rows in the well plate the same as the order of elements in the periodic table?

3. Controlling Variables: If the manipulated variable is the alkaline earth metal added to the chemicals, what is the responding variable in this investigation? (what are you looking for in the reaction?)

4. Predicting: Write a prediction of reactivity of the alkaline earth metals Most reactive: To Least reactive:

Records: Record the amount of precipitate that forms and the precipitate color.

Key: = No Precipitate

= Some Precipitate

= Lots of Precipitate

Carbonate (CO4) Sulfate (SO4) Chromate (CrO3)

Mg Mg Mg

Sr Sr Sr

Ba Ba Ba Analysis and Conclusions: 1. Observing: What evidence did you observe of a chemical change occurring in any of the wells?

2. Analyzing Data: Which alkaline earth metal formed the smallest number of precipitates; Magnesium, Strontium, or Barium?

3. Analyzing Data: Which alkaline earth metal formed the most precipitates; Magnesium, Strontium, or Barium?

4. Drawing Conclusions: Based on your data, list the alkaline earth metals in order of their reactivity, from most reactive to least reactive

Most: Middle: Least

What is the relationship between reactivity and the location of each alkaline earth metal in the periodic table?

5. Evaluating and Revising: Was your prediction correct?

6. Predicting: Group 1A in the periodic table contains alkali metals. Based on your data from this lab, which element in Group 1A, other than francium, would you predict to be most reactive?

7. Predicting: Can the results for reactivity in this investigation be applied to the elements in Group 7A? (take a close look at the background information) Explain.