In the Classroom
Matching Element Symbols with State Abbreviations A Fun Activity for Browsing the Periodic Table of Chemical Elements Klaus Woelk Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409-0010;
[email protected] In every introductory chemistry course, the periodic table of the elements is eventually introduced as a valuable and rich source of information. It separates the known elements into groups and periods, organizing them with respect to similar qualities (e.g., metals, nonmetals, and metalloids). It helps explain periodic trends such as atomic and ionic radii, electro negativity, covalency, and lattice energy, and in time will be used to represent atomic electron configurations according to the Aufbau principle. Periodic tables include information about the average atomic mass of elements and thus are essential to solving problems in elemental analysis, stoichiometry, and con centrations of reactive solutions. This richness of information, however, comes at a price: namely, the anxiety at facing more than 100 more or less unfamiliar combinations of letters. To the chemistry novice, these combinations often seem arbitrary or counter-intuitive (e.g., the symbol for iron is Fe, not Ir), and instructors could spend much time explaining the origin of each element name and symbol. Developing and Using This Activity To lessen students’ anxieties, I often conduct a fun activity in which students are challenged to hunt for matches between the two-letter state abbreviations of the United States used by the postal service and the chemical element symbols found in the periodic table. Entertaining activities and games are known
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to provide alternative ways to engage students in course mate rial and enhance learning (1). Comparable to other approaches (2–4), the activity described here promotes familiarity with the “building blocks” of chemistry in a fun yet also competitive way. Therefore, it should not be mistaken as a mnemonic for memorizing particular elements. The matches are only accidental and do not relate element names to states, countries, or other geographic locations. (For an analogous activity with element symbols not relating to chemical properties per se, see ref 5). The analogy is based purely on the fact that element symbols are abbreviations for the full names of chemical elements in the same manner as two-letter postal codes are abbreviations for the full names of states (6). Still, it might be worth mentioning during or after the activity that many element names have indeed been derived from geographical locations such as continents or countries (Am, Eu, Fr, Ge, Po), states or regions (Cf, Ga, Ru, Sc), cities or villages (Db, Ds, Er, Bk, Hf, Ho, Sr, Tb, Y, Yb), or in the case of Rh from a river (7). As a starting point for the activity, I use an interactive presentation slide (see the online supplement) initially showing a map of the United States of America that includes the state borders.1 Because the state abbreviations of Alaska (AK) and Hawaii (HI) do not match chemical element symbols, a map of the contiguous 48 states is adequate. As shown in Figure 1, a mouse click on a state for which the abbreviation matches an element symbol reveals a photograph showing a sample of the
Figure 1. Detail from an interactive slide (see the online supplement) intended to assist in finding matches between U.S. two-letter state abbreviations and chemical element symbols. (A) Clicking the area for the state of Missouri (abbreviated MO) opens a photograph of a rod of molybdenum (Mo).2 (B) Upon a subsequent click, the photograph of the molybdenum rod is replaced by a box similar to the typical boxes in periodic tables, in this case for molybdenum.
© Division of Chemical Education • www.JCE.DivCHED.org • Vol. 86 No. 10 October 2009 • Journal of Chemical Education
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In the Classroom
element.2 This photograph appears at or close to the state’s loca tion on the map, so that it does not interfere with other states. For example, the state abbreviation for Missouri (MO) matches the element symbol for molybdenum (Mo). Clicking the state of Missouri opens a photograph of a molybdenum rod that covers nearly all of Missouri on the map (Figure 1A). A subsequent click on the photograph of the molybdenum rod displays a box similar to the typical element boxes in periodic tables showing the element symbol, name, atomic number, and average mass of the element (Figure 1B). Ideas for Incorporating the Activity Consider Forming Teams Depending on the class size, teams can be formed and team captains selected. Teams of four–six students are ideal if the periodic table in a textbook is used. Teams of any size may be employed if a large periodic table is displayed in the classroom. Only team captains should be allowed to speak for their team. Alternatively, the activity may be conducted as an individual student challenge, as described below. Elicit Students’ Responses The teams take turns suggesting a state for which the state abbreviation matches an element symbol. If the suggestion is correct, click inside the suggested state’s map outline to reveal the element picture. Have the team captain name the element and share anything the team knows about it or its position in the periodic table. There are 15 state abbreviations that correspond to the symbols of the chemical elements as listed in Table 1. Engage Students with Element Facts Take advantage of the students’ attention to the two-letter combination to briefly explain important facts or typical prop
erties of the specific element. This way, additional knowledge is presented and learning may be smuggled into the activity. Also, mention the particular position of the element within the periodic table. For example, the Missouri–molybdenum example could be used to introduce transition metals (see Table 1). Finally, click the element photograph to reveal the element symbol and related information. Wrap Up the Activity Students will not necessarily discover all possible com binations. Experience shows that Md, Mt, Nd, Sc, and Pa are particularly challenging. When no more suggestions are offered, you may reveal the remaining possibilities or simply conclude the activity. Assign as an Individual or Take-Home Challenge The matching game can also be conducted as a timed indi vidual classroom activity or as a take-home challenge. I have suc cessfully proctored this kind of challenge for 8th grade students using a single-page instruction sheet (see the online supplement) that shows a map of the U.S. with state borders1 and a table with 15 rows to be filled. The challenge consists of two consecutive steps as indicated by instructions listed on the sheet:
1. Write as many state abbreviations as you know into the map of the United States of America.
2. Use a periodic table of the elements to find chemical elements for which the element symbol matches the ab breviation of a state. (Hint: 15 state abbreviations match chemical element symbols.)
As an indication of how to complete the table, the table’s first row is filled in with the California (CA)–calcium (Ca) analogy. This particular analogy is often the first students find when browsing the periodic table. The last column of the table
Table 1. Relating the 15 Two-Letter State Abbreviations for the States of the U.S. That Match Element Symbols to Those Elements State Abbreviations
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State Name
Element
Element Symbol
Example Topics To Introduce
AR
Arkansas
Argon
Ar
Gases, noble gases, nonmetals
AL
Alabama
Aluminum
Al
Metals, main group elements
CA
California
Calcium
Ca
Alkaline earths, essential elements
CO
Colorado
Cobalt
Co
Transition metals
GA
Georgia
Gallium
Ga
Main group elements, semiconductors
IN
Indiana
Indium
In
Main group elements
LA
Louisiana
Lanthanum
La
Lanthanides, inner transition metals,
MD
Maryland
Mendelevium
Md
Actinides, inner transition metals, radioactivity
MN
Minnesota
Manganese
Mn
Transition metals, essential trace elements
MO
Missouri
Molybdenum
Mo
Transition metals, essential trace elements
MT
Montana
Meitnerium
Mt
Synthetic elements, radioactivity
NE
Nebraska
Neon
Ne
Gases, noble gases, nonmetals
ND
North Dakota
Neodymium
Nd
Inner transition metals
SC
South Carolina
Scandium
Sc
Transition metals
PA
Pennsylvania
Protactinium
Pa
Actinides, inner transition metals, radioactivity
Journal of Chemical Education • Vol. 86 No. 10 October 2009 • www.JCE.DivCHED.org • © Division of Chemical Education
In the Classroom
is reserved for the instructor who may want to check off correct suggestions. Alternative Versions for Other Countries The suggested activity is certainly not limited to matching element symbols with U.S. state abbreviations. It can similarly be conducted in other countries or regions using other commonly known two-letter combinations. As an example, a list of element symbols matching two-letter combinations used to identify administrative districts on German automobile license plates is included in the online supplement. Literature Cited 1. See for example: Russell, J. V. J. Chem. Educ. 1999, 76, 481– 484. 2. Eichstadt, K. J. Chem. Educ. 1993, 70, 37. 3. Palmer, J.; Brosnick, L. J. Chem. Educ. 2005, 82, 517. 4. Thomas, N. C. J. Chem. Educ. 2009, 86, 181–184. 5. Earl, B. L. J. Chem. Educ. 1991, 68, 1011. 6. United States Postal Service Official USPS Abbreviations Web Page. http://www.usps.com/ncsc/lookups/abbreviations.html (ac cessed Jul 2009). 7. For more information see the home page of WebElements. http:// www.webelements.com (accessed Jul 2009).
for educational purposes. Copyright: Nations Online Project, http:// www.nationsonline.org/ (accessed Jul 2009). 2. Photographs for the noble gas elements Ne and Ar were ob tained from Wikipedia (http://www.wikipedia.org/ ) and used under the Creative Commons Attribution ShareAlike 2.5 License: http://creativecommons.org/licenses/by-sa/2.5/ (accessed Jul 2009). Photographs of all other element were obtained from WebElements, http://www.webelements.com/ (accessed Jul 2009), with permission from the copyright holder Mark J. Winter (Department of Chemistry, The University of Sheffield, Sheffield, UK). The WebElements photographs of Mn, Ga, Pa, and Sc originate from the CD, Walking Tour of the Elements ( J. L. and V. R. Marshall, University of North Texas), who kindly granted permission to use them. The WebElements photographs of Co, Ca, Nd, and La are from The Element Collection/Element Displays (Copyright The Red Green & Blue Company, 2003), who kindly granted permis sion to use them.
Supporting JCE Online Material http://www.jce.divched.org/Journal/Issues/2009/Oct/abs1205.html Abstract and keywords Full text (PDF) Links to cited URLs and JCE articles Supplement
Interactive presentation slide to conduct the activity in the classroom (formatted for Microsoft Office PowerPoint 2003 and Microsoft Office PowerPoint 2007)
One-page version (PDF) of the activity for individual challenge
List of element symbols matching two-letter combinations on German license plates
Notes 1. The map used in the presentation slide in the online supple ment was obtained from the Web site http://www.nationsonline.org/ oneworld/usa__blank_map.htm (accessed Jul 2009) and is free to use
© Division of Chemical Education • www.JCE.DivCHED.org • Vol. 86 No. 10 October 2009 • Journal of Chemical Education
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