The Periodic Table of the Elements - ACS Publications

Oct 10, 2009 - I wanted to start out by taking a look at the history of the periodic table of the elements. Many scientists had a hand in its developm...
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News from Online: The Periodic Table of the Elements by Lynn Diener

What could be more central to the study of chemistry than the periodic table of the elements? It combines all of the known elements into a tabular form, arranged by atomic number, grouping elements together by similarities in their chemical properties (Figure 1). That is exactly what this year’s National Chemistry Week is celebrating—and it is no accident that this is the 140th anniversary of Mendeleev’s periodic table. A Historical Look at the Table I wanted to start out by taking a look at the history of the periodic table of the elements. Many scientists had a hand in its development. A site hosted by Western Oregon University gives an overview of those contributions (1). It’s fairly common for a history of the periodic table to cover contributions by Newlands, Rutherford, and Moseley. This history also talks about somewhat more obscure contributors, for instance Henning Brand, who discovered the element phosphorus and Johann Dobereiner, who postulated the law of triads (2). I think it’s also beneficial for students to see the original periodic table proposed by Dmitri Mendeleev (Figure 2). They can do that at the Classic Chemistry site at Le Moyne College, where there is a translated version of Mendeleev’s original periodic table with hyperlinks to the elements that were unknown, but proposed, by Mendeleev (3). They can then compare the original table with what it looks like today as they see it in their textbooks or on the classroom wall. They’ll see how similar the two really are. Visionlearning by Anthony Carpi, a professor of environmental toxicology at Cornell University, has a page that goes into a little more detail about the differences between Mendeleev’s original and the current periodic table (4). It also explains the periodicity of the table and electron configuration as it relates to chemical properties. The Periodic Table of the Elements quiz, accessed from a tab at the top of the Visionlearning page, is a fun way for students to test their knowledge of the organization of the table (both historic and current), basic information about the table, and electron configuration. Discovery of Individual Elements A Web page by Norman E. Holden of Brookhaven National Laboratory goes into detail about the discovery of the elements (5). It talks about the individuals who discovered each element, the origin of each element’s name, and often when and where the element was discovered. It has some information for most elements through element 118, but no names for any element after Darmstadtium (atomic number 110). I think it was probably last updated for content in 2001, which would explain this discrepancy. The next Web page, from Sequin Science, has an interactive periodic table with links to information about discovery and naming (6). This site more thoroughly covers the most recent elemental discoveries. Either of these is a great place to send students who are working on any sort of element project for National Chemistry Week.

Figure 1. A modern representation of the periodic table of the elements. This one is taken from Periodic Table Live! in the ChemEd Digital Library.

Figure 2. A photo­graph of Dmitri Mendeleev. Courtesy of Ihde Collection; used with permission.

For any of your students who haven’t heard “The Elements” by Tom Lehrer, you can find dozens of video versions of this song on YouTube. The song sets the elements of the periodic table (circa 1959) to the music of the Major General’s Song from The Pirates of Penzance. I like the version found at (7) because it shows where the elements are on the periodic table, highlighting the elements that were not yet known at the time the song was written in 1959. My students get excited by the elements when they hear this catchy song. The Periodic Table of the Elements It is not difficult to find interactive periodic tables on the Internet. Here, I’ll highlight just a few and describe features I find particularly useful or fun. The Periodic Table Live!, software published by this Journal and now available without charge as part of the Chemical Education Digital Library, is one of my

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Figure 3. A screen capture of Periodic Table Live! and what you will see when you click on a element.

favorites (8). Like many interactive periodic tables you can click each element to get information about that element, its discovery, uses, and chemical properties (Figure 3). I’m particularly fond of the Jmol crystal structures. You need to have Java enabled on your computers in order to see these structures. In looking at carbon crystal structures, students can compare graphite to diamond and even buckyballs. Students begin to understand how one element can have such distinct forms by looking at these crystal structures. There are also videos of reactions that are available for many elements. These videos highlight reactions of the element with air, water, acid, and base. I find that my students like the explosive reactions best, for instance the reaction of hydrogen with air. But my favorite feature of Periodic Table Live! is its ability to chart and sort different atomic and physical properties of the elements (Figure 4). For example, students could select the atomic number and electronegativity for any selection of elements. This allows students to see the periodic trend of electronegativity laid out before their eyes. What better way is there for students to understand the periodicity of the table than to see it graphed in front of them? I think this feature is so valuable because it exposes students to graphs and requires them to engage their ability to interpret graphs. They also have the ability to easily change the graphs to get at the information they need. Though not as focused on the chemistry of individual elements, you may find that the Periodic Table of Comic Books is a good way to catch your students’ interest (9). There are comics for most elements up to meitnerium. They are real comics that the site authors have located and scanned for their Web site. We present one of their comics here (Figure 5), but there is really something for everyone: Wonder Woman, Star Trek, Ricky Nelson, Legion of Super Heroes, Batman, and Superman, to name just a few. There is a Disney comic where Donald Duck gets a bump on the head and starts talking about making Speckled Nitrogen. In a WonderWoman comic, you focus in on the Atom World where the queen is a proton and her automaton slaves are neutrons—it’s definitely worth a look from you and your students. The site only presents a small portion of a particular comic, which includes a reference to the element in question. For 1164

Figure 4. The chart and sort feature of Periodic Table Live! In this shot we are exploring the relationship between atomic number and atomic mass.

Figure 5. This comic of William Lipscomb was drawn for The Periodic Table of the Comic Books by Tony Gleeson. Lipscomb, a professor at Harvard University, won the Nobel Prize in 1976 for his work on boranes. He is also an active participant in the annual Ig Nobel awards. The illustration shows Lipscomb next to Hypho-Man, his 1976 Nobel Prize certificate, and a model of the conjuncto-borane, B10H16. The drawing is done in the style of Gil Kane, the artist who drew The Atom for DC comics during the 1960s. Copyright 1999 by Tony Gleeson. Used with permission.

most of the comic strips the site authors give an explanation of the comic and often address the science behind it. They’re not afraid to point out where the comics did, or did not, handle the scientific content well.

Journal of Chemical Education  •  Vol. 86  No. 10  October 2009  •  www.JCE.DivCHED.org  •  © Division of Chemical Education 

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Another take on an interactive periodic table can be found at The Periodic Table of Videos out of the University of Nottingham (10). My students have an easy time connecting with videos and tend to retain information they see and hear. The videos vary in length but most are 3 to 5 minutes long. The videos go back and forth between one scientist who handles the element in question and another who talks about it. You learn about the history, chemical properties, and other interesting stories about the elements. The strength of these videos is the chemistry and the high degree of fun the participants have. Everyone engaged in the process seems to be having a good time. This series of videos doesn’t always take all of the safety precautions I would like to see, for instance if you watch the video on sodium, you will see a bit of exploding sodium picked off a table with gloved fingers and later they realize some ended up on the video camera. You may want to preview the videos before having your students watch them. Several games on the Sheppard Software site can help your students learn about the different elements in an interactive way (11). There are eight different games, focused at different levels (from beginner to master, probably good for high school through introductory college levels). The games focus on helping students to learn the periodic table of the elements in different ways—some are drill and practice type games, others are more exploratory teaching about chemical properties. There is also a Mystery Elements game in an interactive periodic table from the Teacher’s Domain. Students place mystery elements on the periodic table with some information given about the atomic properties, chemical properties, or electron configurations. It helps students to test their knowledge and see if they understand concepts such as atomic mass and atomic number (12). Atoms No study of the periodic table would be complete without a discussion of atoms and their make-up. The Nondestructive Testing Resource Center has a tutorial that explores the atom; it covers protons, neutrons, electrons, isotopes, radioactivity— and more if your class is interested (13). The Jefferson Lab has an introduction to the atom; it’s an interactive tutorial that talks about protons, neutrons, electrons, quarks, and gluons (14). This tutorial may be more appropriate for a college-level class. After students have a sense of what makes up an atom, they may enjoy making their own using the Atom Builder from the Public Broadcasting Service (15). Here students start with a hydrogen atom, then use quarks to build neutrons and protons, which they add to the hydrogen to increase the size of the atom. At the same time, they also add electrons as needed to balance the charge of the nucleus. The Particle Adventure from the Particle Data group at Lawrence Berkeley National Lab goes beyond talking about atoms: they discuss accelerators and particle detectors, string theory and dark matter. Normally I don’t cover this in my classes, but if you choose to enter The Standard Model selection on the Web page, you will find a fairly basic, interactive, exploration of the atom (16).

Figure 7. The Jmol structure for glycine as seen in Molecules 360 feature on the ChemEd DL home page.

Molecules Let’s move to a somewhat larger scale by putting elements together in interesting ways. ChemThink has a variety of nice tutorials that have informative text, hands-on activities, and questions to facilitate thought and exploration. These tutorials are available for educators and students after you create a free account (17). I’ve put ChemThink in this section because of their Covalent Bonding tutorial, but there are a variety of tutorials available on the atom, ionic bonding, chemical reactions, and more. The interactive tutorial on covalent bonding is very helpful when I am teaching students about molecules. One of the interactive elements of this tutorial allows students to play with hydrogen atoms, watching them covalently bond when you bring them close enough to each other. Seeing molecules in three dimensions helps students to understand them better. They get a sense of how elements connect to each other and understand bond angles. The Chemical Education Digital Library houses a particularly useful collection of small molecules called Molecules 360 (18). Some examples of small molecules you can find housed here are water, ozone, methane, and even the amino acid glycine (Figure 7). Jmol gives students an opportunity to see and rotate these molecules with a mouse. Depending on the level of your course, you could have students look at everything from bond distances to modes of vibration. The periodic table of the elements is at the center of any study of chemistry. As the American Chemical Society’s ­National Chemistry Week 2009 theme states—“It’s Elemental!” I hope that some of the resources in this article will help you celebrate National Chemistry Week and beyond with your students. Literature Cited and World Wide Web Addresses (all sites accessed Jul 2009)

A Historical Look 1. A Brief History of the Development of Periodic Table. Western Oregon University. http://www.wou.edu/las/physci/ch412/perhist. htm. 2. Scerri, E. The Role of Triads in the Evaluation of the Periodic Table: Past and Present. J. Chem. Educ. 2008, 85, 585–589. 3. The Classic Chemistry site is at Le Moyne College, http://web. lemoyne.edu/~giunta/index.html; information about Mendeleev is at http://web.lemoyne.edu/~giunta/mendeleev.html.

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Reports from Other Journals 4. Carpi, Anthony. The Periodic Table of the Elements. Visionlearning. http://www.visionlearning.com/library/module_viewer. php?mid=52&mcid=&l=.

Discovery of the Elements 5. Holden, N. E. 2001. History of the Origin of the Chemical Elements and Their Discoverers. Prepared for the 41st IUPAC General assembly in Brisbane. Hosted on the Brookhaven National Laboratory Web site. http://www.nndc.bnl.gov/content/elements.html. 6. Trapp, D. 2000. The Chemical Elements: Their Discovery and the Origins of their Names. http://web.me.com/dtrapp/Elements/ elements.html. 7. The element song. A video of “The Elements”, a song by Tom Lehrer. http://www.youtube.com/watch?v=GFIvXVMbII0&NR=1.

The Periodic Table of the Elements 8. The Periodic Table Live! JCE Software, 3rd edition. http://www. chemeddl.org/collections/ptl/index.html. 9. Selegue, J. P.; Holler, F. James. The Periodic Table of Comic Books. http://www.uky.edu/Projects/Chemcomics/. 10. The Periodic Table of Videos. University of Nottingham. http:// www.periodicvideos.com/. 11. Chemistry Games. Sheppard Software. http://www.sheppardsoftware.com/Elementsgames.htm. 12. Periodic Table of the Elements. The Teachers’ Domain. http:// www.teachersdomain.org/asset/phy03_int_ptable/.

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Atoms 13. Subatomic Particles. Nondestructive Testing (ND) Resource Center. http://www.ndt-ed.org/EducationResources/HighSchool/ Radiography/subatomicparticles.htm. 14. All About Atoms. Jefferson Lab. http://education.jlab.org/atomtour/. 15. Atom Builder, You Try It. A Science Odyssey from the Public Broadcasting Service. http://www.pbs.org/wgbh/aso/tryit/atom/. 16. The Particle Adventure: The Fundamentals of Matter and Force. Particle Data Group at Lawrence Berkeley National Laboratory http://particleadventure.org/.

Molecules 17. ChemThink. http://www.chemthink.com/chemthink.htm. 18. Molecules 360. Chemical Education Digital Library. http://www. chemeddl.org/collections/molecules/index.php.

Supporting JCE Online Material

http://www.jce.divched.org/Journal/Issues/2009/Oct/abs1163.html Abstract and keywords Full text (PDF) with links to cited URLs and JCE articles

Lynn Diener is a member of the Science Department, Mount Mary College, Milwaukee, WI 53222; [email protected].

Journal of Chemical Education  •  Vol. 86  No. 10  October 2009  •  www.JCE.DivCHED.org  •  © Division of Chemical Education