Activity pubs.acs.org/jchemeduc
Using a Hands-On Method To Help Students Learn Inorganic Chemistry Nomenclature via Assembly of Two-Dimensional Shapes Amalio Garrido-Escudero* Environmental Engineering and Toxicology Department, Catholic University of San Antonio, Guadalupe, Murcia 30107, Spain S Supporting Information *
ABSTRACT: Learning chemical nomenclature is part of many students’ first contact with chemistry. Generation after generation of students has come to love chemistry after successfully overcoming the “barriers” of the first difficulties in the learning process. Other students fail and abandon the study of chemistry forever. A tool named FORMula, which is a combination of the words FORM (i.e., shape) and formula, has been developed to reduce or eliminate barriers in the process of learning inorganic chemistry nomenclature. The method uses two-dimensional polygonal or circular shapes and panels (representing ions) that can be assembled only in ways permitted by the rules of nomenclature to create compounds. This method can be used to help students in determining the name of a compound given its chemical formula and in determining a chemical formula of a compound when given its name. This method can help any new chemistry student, but particularly students affected by color-vision deficiencies, severe visual impairments, or blindness. Students can practice individually or in groups, in the classroom or at home. The method can also be used to help understand the periodic table, element properties (such as oxidation states), the stoichiometries of chemical reactions, and the application of nomenclature rules in inorganic chemistry. KEYWORDS: First-Year Undergraduate/General, High School/Introductory Chemistry, Inorganic Chemistry, Hands-On Learning/Manipulatives, Minorities in Chemistry, Nomenclature/Units/Symbols, Periodicity/Periodic Table
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testing of the new concepts. The spiral of learning can start with any one of the four elements, but usually begins with a concrete experience. In the author’s experience, students usually face five barriers to learning chemical nomenclature: (a) Lack of familiarity with elements and the periodic table (b) Lack of knowledge regarding element electronic configurations and oxidation states (c) Difficulties with identifying chemical compound types (d) Lack of understanding of systematic chemical nomenclature and rules (e) Difficulties in understanding what a chemical formula or its name represents From observations of student behavior, it appears that these barriers occur in the early stages of the learning process, in the “concrete experience” stage. A method was developed to improve the spiral learning through sensorial training in abstract concept areas such as chemical nomenclature. The developed method FORMula, which is a combination of the words FORM (i.e., shape) and formula, is aimed at facilitating the “concrete experience” stage of the complete learning process. The method uses twodimensional polygonal or circular shapes and panels (represent-
tatistics show that 3.3 million people in the United States (2.7% of the total population) have a severe visual impairment or blindness.1,2 Blindness, as described by the U.S. definition, is a best-corrected visual acuity of 20/200 or worse in the better-seeing eye. Low vision is defined as a bestcorrected visual acuity of less than 20/40 in the better-seeing eye (excluding those categorized as blind by the U.S. definition).1 Visually impaired beginner students are often discouraged from actively understanding chemical nomenclature. Several authors have described methods and devices to help blind students learn chemistry, especially in the laboratory.3−6 Recently, a QR-coded audio periodic table of the elements has been developed to teach chemistry to blind and visually impaired students under a mobile-learning environment.7 The learning process can be viewed as a cycle in which the processes of addressing (planning) → doing → sensing (observing) → thinking occur in an endless cycle.8 Sensing, observing, and experimenting or experiencing have traditionally been identified as some of the core steps in the learning process. For instance, Kolb and Fry published their experiential learning model (ELM),9 consisting of four elements that can repeat their sequence on a continuous basis: concrete experience, observation and reflection on that experience, formation of abstract concepts based upon the reflection, and © XXXX American Chemical Society and Division of Chemical Education, Inc.
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ing ions) that can be assembled only in ways permitted by the rules of nomenclature to create compounds. This method can be used to help students in determining the name of a compound given its chemical formula and in determining a chemical formula of a compound when given its name. The FORMula method has been tested with groups of nonvisually impaired beginner students. Two groups of beginner students were tested. None of the students had studied chemistry before. For the first group of beginner students, their first contact with chemistry was through the use of the FORMula method to initiate the learning process regarding elements, compounds, formulation, and the periodic table. The second group of beginning students was used as a reference test group and the learning process was initiated using conventional teaching methods. On average, the first group learned more quickly and showed greater confidence levels in formulation than the second group did. Interesting behavior was observed after a short period of time using the FORMula method regarding the mental building of compounds without using physical shapes. This behavior indicates that FORMula is ideal in the early initiation phases of the learning process. All chemistry teachers involved using the FORMula method, including those from ONCE (Spanish National Blind Organization), are confident about using the method to accelerate the learning process and increase the success of beginner students in chemistry. Blind or visually impaired students require bigger shapes and the substitution of colors by textures.
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Table 1. Shapes Used for Each Periodic Table Group Periodic Table Group
Shape Used
Exceptions
1 and 11 1 2 and 12 2 3 and 13 3 4 and 14 4 5 and 15 5 6 6 16 6
Except when behaving as anion (2−) in oxygen (oxide) and sulfur (thioacids), in which case the 6B shape is used
7 and 17 7 8 8
element) are present in the set. Equal oxidation-state numbers may have different shapes, depending on the type of compound that can be generated by that particular shape. Even the color or texture of the shape can provide information on the type of compound that the ion can be part of. The panels can be stored in a multiple-sectioned box (see the photo in the Supporting Information) with a similar organization to that of the periodic table. Each panel of the same element is stored in the section for the corresponding group of the periodic table. This means that in the section for potassium, there are panels in sufficient number to allow the creation of compounds with more than one potassium atom and all of the oxidation states of the element. In this case, only one oxidation state is possible, +1. The panel in that section is shown in Figure 2 as an example. The recommended number of shaped pieces (or panels) is 160, taking into account that each side of a shape can be used for a different element.
FORMula METHOD
Description of the Shapes
The method uses a set of shapes made of any material (paper, plastic, wood, or metal). The set of shapes forces students to familiarize themselves with the elements (including their symbols), the periodic table, and electronic configurations and oxidation states. The shapes are polygonal or circular, as shown in Figure 1. The number of polygon sides indicates the
Figure 1. Shapes used in the FORMula method.
Figure 2. Example of the panel for the potassium ion: the circle represents the group and the squared concavity the 1+ charge.
group within the periodic table of the elements, according to Table 1 (an exception is made for groups 1 and 11, which use circles and are considered as having one side for the purposes of this rule). Oxidation states are represented as squared concavities (−) or convexities (+) on the polygon flat sides. The number of concavities or convexities represents the oxidation state of that ion. Only possible ions (oxidation state numbers of the
Students can identify a possible ion from its panel by observing: the number of sides of the polygon, the element name on it (even in Braille), the squared concavity or convexity number giving the oxidation state, and the color or texture showing the type of compound the ion can be part of (Figure 3). FORMula panels are designed in a prefixed way to guarantee the proper assembly of possible existing chemical B
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that is shown by this compound. Nitrogen has two possible oxidation states in salts and oxoacids, 5+ or 3+. The higher oxidation state (5+) gives salt names ending in “-ate”. The lower oxidation state (3+), takes the ending “-ite” as a suffix. Therefore, students use the 3+ oxidation state for nitrite (Figure 6A). Students add two types of oxide (2−) ions to the
Figure 6. Potassium nitrite assembly process.
central ion (Figure 6B) to give the nitrite ion. To achieve neutrality, students use the potassium (1+) ion, as required by the given name. This gives the complete ionic compound (Figure 6C). To write the formula, according to IUPAC nomenclature rules, the students begin with the positive part of the compound, K and then negative part, the nitrite ion, NO2−. Therefore, the final formula is written as KNO2.
Figure 3. Potential information that could be included on an ion panel: texture (a), shape (b), oxidation state or number of convexities or concavities (c), element name (d), element symbol (e), electronic configuration (f), prefix (g), suffix in acids, oxides or salts (h), atomic number (i), atomic mass (j), oxidation state (k), period number (l).
The Chemical Name from the Chemical Formula
The procedure for application of the method can be followed more easily by looking at an example; write the name for SO2(OH)2 or H2SO4, as shown in Figure 7. This step consists
compounds. Any intention to form nonexistent compounds will lead to a lack of complete matching of panels. The handling of panels (Figures 4 and 5) facilitates familiarization by the students with the elements, the periodic
Figure 4. Examples of two panels for group 14 elements from a Spanish-language set used for all students.
Figure 7. Example for FORMula compound to be named.
of identifying the type of compound. Students easily identify the two hydroxide (1−) and two oxide (2−) ions that are bonded to the central atom. Consequently, it is an oxoacid compound. Then, the students identify the central atom, which in this case is sulfur. The oxidation state of the central atom is 6+, represented as the ionic charge number. Sulfur can form oxoacids with 4+ and 6+ oxidation state named as sulfurous acid and sulfuric acid, respectively. Taking this information into account, students write a scientific name dihydrogen sulfate or the common name, sulfuric acid, according to IUPAC nomenclature rules.10 Some other examples of compounds represented by panels are shown in Figure 8 for the formulas and names listed in Table 2.
Figure 5. Examples of polygonal panels for vanadium ions (different oxidation states) used for visually impaired students.
table, electronic configurations, oxidation states, and the types of compounds formed by an element. By simply observing and browsing the complete set, students are overcoming three of the learning barriers (a, b, and c barriers described above). The remaining two barriers are (d) related to the IUPAC chemical nomenclature rules and (e) compound formula and name.10 We can better understand how the method works by considering two common questions: find the formula when given the name and the reverse.
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CONCLUSIONS The use of physical aids to teach inorganic chemical nomenclature to visually impaired or blind students can overcome several learning constraints. Physical aids such as the method proposed in this paper will also significantly enhance the learning curves of the majority of students. The process of familiarization with the elements, symbols, and
The Chemical Formula from the Chemical Name
The procedure for application of the method can be followed more easily by looking at an example; find the formula of potassium nitrite, the salt of a nitrogen oxoacid. First, students find the central atom of the molecule, in this case, nitrogen. After the central atom is found, students find the oxidation state C
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Activity
ACKNOWLEDGMENTS Special thanks to M. Tejera, S. Juanes, A. Arrizabalaga, N. Zambrano, J. Garcia,́ and Ana G. Conejero for support with graphic and template preparation, and to J. M. Villar (ONCE) for his support and feedback.
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(1) National Eye Institute. http://www.nei.nih.gov/eyedata/pbd_ tables.asp (accessed Jun 2013). (2) Ferris, F. L. Arch. Ophthalmol. 2004, 122 (4), 451−452, http:// archopht.jamanetwork.com/article.aspx?articleid=416235. (3) Graybill, C. M.; Supalo, C. A.; Mallouk, T. E.; Amorosi, C.; Rankel, L. Low-Cost Laboratory Adaptations for Precollege Students Who Are Blind or Visually Impaired. J. Chem. Educ. 2008, 85 (2), 243. (4) JCE staff.. More Than Meets the Eye: Nonvisual Observations in Chemistry. J. Chem. Educ. 2000, 77 (9), 1104A. (5) Smith, D. Teaching Aids for Visually Handicapped Students in Introductory Chemistry Courses. J. Chem. Educ. 1981, 58 (3), 226. (6) Neppel, K.; Oliver-Hoy, M. T.; Queen, C.; Reed, N. A. Closer Look at Acid−Base Olfactory Titrations. J. Chem. Educ. 2005, 82 (4), 607. (7) Bonifácio, V. D. B. QR-Coded Audio Periodic Table of the Elements: A Mobile-Learning Tool. J. Chem. Educ. 2012, 89, 552. (8) Juch, B. In Personal Development: Theory and Practice in Management Training; Shell International, Wiley: New York, 1983; p 244. (9) Kolb, D. A.; Fry, R. Theories of Group Processes. In Toward an Applied Theory of Experiential Learning; Cooper, C., Ed.; John Wiley: London, U.K., 1975. (10) Conelly, N. G.; Damhus, T.; Hartshorn, R. M; Hutton, A. T. Nomenclature of Inorganic ChemistryIUPAC Recommendations 2005; Royal Society of Chemistry: Cambridge, U.K., 2005.
Figure 8. Examples of applications of the FORMula method for different compounds list in Table 2.
Table 2. Compounds Shown in Figure 8 Identification Letter
Chemical Formula
Common Name
A B C D E F G
H2O KCl KClO4 AlCl3 HNO3 SnCl2 SnCl4
Water Potassium chloride Potassium perchlorate Aluminum chloride Nitric acid Tin(II) chloride Tin(IV) chloride
REFERENCES
periodic table organization can be achieved through the use of these panels. The panels provide information regarding the periodic group of the elements through the number and type of sides of the polygon. The numbers of concavities and convexities for each element set of panels will help students to become familiar with and easily remember their oxidation states and the relationship with their positions within the periodic table and the types of compounds they can form. In addition to the benefits for individual students’ work and the execution of autocorrection exercises, teamwork and teacher presentation are significantly facilitated. Software applications could be developed to support teachers and other students, in addition to visually impaired ones, by substituting the use of physical panels.
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ASSOCIATED CONTENT
S Supporting Information *
A suggested list of 62 panels (in Spanish) and an example of a FORMula box. This material is available via the Internet at http://pubs.acs.org.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest. D
dx.doi.org/10.1021/ed300224m | J. Chem. Educ. XXXX, XXX, XXX−XXX
