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How the Periodic Table Challenge Works

Interactive Learning Paradigms Incorporated

Intro and Philosophy

The Periodic Table Challenge is an interactive web-based teaching resource that features a blank periodic table. There are two versions - the Classic Challenging Version in which the user has to complete a blank table before receiving a score and the Easier Instant Version in which the user receives feedback immediately after filling in each element.

I designed the Classic Version for my upper division courses in which the student must know the periodic table. I didn't say "memorize", although that's what it may appear to be. But in order to write essays you have to know the alphabet, right? If you are attending a chemistry seminar and someone mentions an iron-containing compound, you have to know that Fe is in 8th column over, has some chemistry similar to Ru and has 5 d-electrons if it is in the 3+ valence state.

OK, here's how it works

The Classic Challenging Version:

1. The Periodic Challenge page contains two very important components which may not be immediately obvious. First, the page is an HTML form which means that it is configured to send any data that you might enter to our web server. Second, the blank periodic table is displayed. The table you see is simply an HTML table, so it is pretty easy to construct. The boxes where you enter your answers are form input fields which permit only 0 to 2 characters of input. Everything up to this point you can check out on your own by viewing the source document from your browser.

   Note: The next step is new as of September 2004. See the Revision History below on how our web server used to handle the grading task.

2. When you hit the Submit button, our web server's form parser echoes your data to the results page. There, a JavaScript routine grades your results. All it has to do is compare the name of the box you filled in to the value you entered. If they match then you're correct. If the two don't match then you're incorrect. If you didn't put in an answer, then that is noted, too. In programming terms, the grading is a simple "with x = 1 to 112" loop and the rest is just table formatting and extras like the hints/comments or an occasional graphic.

The Easier Instant Version:

As with the Challenging Classic Version, everything is set up as an HTML table. But this time, the data is not submitted and then redrawn. Instead, as soon as you enter your guess for an element, a JavaScript routine immediately checks the answer and adjusts your score. If you answer is wrong, it replaces it with a "*" so you can identify which ones are not yet correct.

In addition, this version sports an auto-hints feature. When this is turned on, you'll receive a popup dialog if you have guessed wrong more than 3 or more times on a particular element. The hint is the first letter of the element if the element symbol has two letters. If the element symbol has only one letter, the hint tells you so.

Another nice touch in this version is that it tells you the number of incorrect attempts you have made. After all, anyone can get all 112 elements, but only the best will do it without making any mistakes. I have also added a timer which stops when the table is correctly completed. This enables our visitors to have a contest to see who can complete the table with the fewest errors in the shortest amount of time. To make the determination of a winner fair, I suggest adding a predefined time penalty (5 or 10 seconds) for each incorrect answer; this is a feature I can add at a later date.

Revision History

• Future Plans. Some optional variations we may add in future releases include:
  • Multiple choice - each cell in the table will have 5 choices in a pull-down menu.
  • Drag and drop - we give you the elements, you drag them to where they belong.
  • Quick Peek - a periodic table will flash up for a brief instant each time you press a button.
  • Suggestions? Send them along to us.

• September 3, 2018. 2.2b.4 - Added Nh, Fl, Mc, Lv, Ts, and Og. There's really not much point to having these elements here except for completeness sake. It's not like we do any chemistry with them. Still, they do make for good trivia questions and add to our alphabet for making clever t-shirts using elemental symbols.

• July 27, 2010. 2.2b.3 - Added a Start Over feature to the Easier Instant Version. This resets the scores, table, and timer back to zero, alleviating some obscure keystrokes that Firefox required. Also changed the timer to start when you enter your first answer rather than when the page loads.

• July 13, 2010. 2.2b.2 - Finally got around to adding Ds, Rg, and Cn...not like you can put any of these in a vial, though.

• March 12, 2007. 2.2b.1 - fixed score/time display issue in Easier Instant Version with Firefox.

• September 10, 2004. Version 2.2a (Challenging Classic Version) and 2.2b (Easier Instant Version. For some unknown reasons, the original AppleScript grading application (see below) stopped working correctly. It appeared to be some sort of bizarre permissions issue or else a conflict with a recent software or OS upgrade. Therefore, I had to rewrite the grading routine using JavaScript. I made two versions of this because a) I saw a need for an "easier version" and b) the new Easier Instant Version can be saved to disk, enjoyed while off-line, and includes some cool new features.

• November 9, 2003. Version 2.1 released. We upgraded to a dual 1 GHz G4 server running Mac OS X. This forced us to replace the Hypercard grading stack with an AppleScript application because, for reasons nobody understands, Apple Computer elected to never release a Mac OS X-compliant version of HyperCard. There are no fundamental changes in this version, although the grading response should be noticeably faster.

• June 9, 2000. Version 2.0.2. Moved from the U of KY web site to ILPI. Different comments are now included for each score. Put a box around the entire table. Added the IUPAC-approved names for elements up to 109 (up from 103).

• October 11, 1999 Version 2.0.1. Made sure an HTTP header is sent with the reply, correcting an error with certain browser/firewall combinations. Fixed a few typos in the hints.

• May, 7, 1999. Version 2.0 debuted. As originally designed, the Periodic Table Challenge did not inform you which elements were correct and incorrect. I prefer this method because it provides additional review by making you figure out which elements are incorrect. However, in Version 2.0 you know have the option of checking the Novice Mode box to reveal your errors. This could be useful when you are first starting out or if you are practicing but don't have a periodic table to consult.

• June 27, 1997. I added a feature which allows you to ask for one random hint or piece of trivia with your score. Some day in the future I'd like to program in a way of returning hints such as "you are missing the element named for the god called Tantalus" or "you have the most radioactive element where the largest element should be" etc., but that's a lot more work.

Selected Viewer Comments

How well do people like the PTC? Here are some examples. If you have kudos or comments, send them along to us. We'd love to hear them and maybe we'll even post them here.
• From a Los Alamos National Laboratory scientist: "It's a humbling experience".

• The PTC was included in a New York Times article in 1998 or 1999. (sorry, we forgot the exact date).

• The PTC was also written up around the same time in Chemical & Engineering News.

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This page was last updated Monday, September 3, 2018 and has been visited 75206 times since its birth on 08/30/96.

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