Experiment #5

Title: Periodic Trends

Purpose: To determine if there are patterns in the properties of metallic elements.

Methods: Reactions involving Li, Na, K, Mg, Ca, and Al can be observed. From the resulting reactions we can determine if there is a pattern of reactivity.

Procedure: Demonstration only! For each reaction below, observe the results and describe what you see.

Data:

  1. Lithium and water
  1. Sodium and water
  1. Potassium and water
  1. Magnesium and water
  1. Calcium and water
  1. Aluminum and water
  1. Calcium and hydrochloric acid (HCl)
  1. Magnesium and HCl
  1. Aluminum and HCl
  1. Magnesium and oxygen (heated)
  1. Aluminum and oxygen (heated)

Post Lab Questions:

  1. In the periodic table below, fill in the atomic symbol for the each element tested. Make sure the symbol is in the appropriate location.

  1. Using the observations made during this demonstration create and justify a periodic trend for chemical reactivity.
  1. Using the observations made during this demonstration create and justify a group trend for chemical reactivity.
  1. Explain the trends you have created for chemical reactivity using the trends for ionization energy and atomic size as a basis.

Conclusion:

Write the following conclusion in paragraph form following the Science Writing Guidelines. Use complex sentences in all sections.

  1. Introductory statement with the purpose or the problem and hypothesis.
  2. Summary of experiment with results. If applicable, ALSO do the following:
  3. Explain whether the results of the lab confirm or refute the hypothesis.
  4. Discuss the experimental design (dependent variable, independent variable, hypothesis).
  5. Describe any real or possible error. If you had real error, explain why this error occurred. If no error occurred, explain why another group had error or theorize where error could occur. Be specific and do not describe a math error--instead re-do the math.
  6. Paraphrase and cite the textbook or other reference material (pg. #, title and author) and explain whether the results of this lab confirm or refute the scientific concepts in the material.
  7. Provide a concluding statement that is evidence-based (facts and data). Remember, no opinions or feelings.

Science Lab Conclusion Rubric

4 / 3 / 2 / 1 / 0
1. Introductory Statement / Clear, concise statement of the purpose or problem, and hypothesis / Unclear, or partially complete statement / Missing or did not follow directions.
2. Summary / All stages of the lab are clearly summarized. / All stages of the lab are discussed, but somewhat unclear or too short. / Missing one stage of the lab in the summary. / Missing multiple stages of the lab in the summary and/or summary is very unclear. / Missing or did not follow directions.
3. Error / Real or possible error is clearly discussed. / Real or possible error is discussed, but explanation is too short or unclear. / Missing or did not follow directions.
4. Textbook or Other Material Reference / Accurate reference with all required information. Clear explanation of confirmation or rebuttal of scientific information in reference material. / Accurate reference, but explanation of reference material is somewhat unclear, too short or slightly flawed. / Minimal explanation or some missing information. / Inaccurate reference and/or some missing information and/or unclear explanation. / Missing or did not follow directions.
5. Concluding Statement / Clear and concise statement with facts and data. / Statement is unclear or lacking facts and data. / Missing or did not follow directions.
6. Writing Guidelines / General Science Writing Guidelines are followed. / General Science Writing Guidelines are followed, but a few minor mistakes are made. / General Science Writing Guidelines are followed, but with multiple mistakes made. / Missing or did not follow directions.
7. Content-Specific Scientific Vocabulary / All content vocabulary is appropriately used and enhances the explanation of scientific concepts. / Some content vocabulary is used appropriately and/or somewhat explains the scientific concepts. / Few or none of the content vocabulary words are used; or vocabulary is used incorrectly.
8. MLA Citation / Proper MLA Citation is present / Missing or did not follow directions.

Total ______/20