March 2024 newsletter: molecular Lewis structures, polyatomic ions and more!

Hello again, I hope you’ve been doing well! In this newsletter, I’ve included the following important updates about

  • *NEW* Molecular Lewis structures!
  • *NEW* Polyatomic ion naming & formula writing!
  • Bug fixes and other improvements

*NEW* Molecular Lewis structures!

Now that has been around for almost four years, I feel like I’ve been able to add many of the fundamental quiz and Dashboard features that would be most useful to a high school or introductory college Chemistry course. However, there are still a number of topics that I want to add to the site, and molecular Lewis structures have been at the top of that list for a while now.

After I finished adding multiple choice options to all of the quizzes back in January, I’ve spent the last several weeks collecting and verifying 227 molecular Lewis structures so I could add them to the Lewis Dot Structures Quiz! Here’s an example of one type of question generated by the quiz:I also added the ability to select molecules that either follow the octet rule or don’t follow it (or both!). Here’s an example of a more challenging question about an octet rule-breaker:

I did my best to avoid resonance structures (for now) and I tested out all of the questions, but if you come across any incorrect structures, bugs or other issues, please let me know. I hope the new molecular Lewis structures are useful for you and your students!

*NEW* Polyatomic ion naming & formula writing

Another popular feature request has been to ask me to add a quiz to help students memorize polyatomic ions, but I never felt that topic was significant enough to justify its own separate quiz. However, I recently realized that I had already entered most of the widely known polyatomic ions in the database for a different quiz, so I added them to the Naming Compounds & Calculating Molar Masses Quiz! Here’s an example of the kinds of questions you can now generate:

There are a total of 37 polyatomic ions available, and the quiz should also accept common (non-IUPAC) names as correct (e.g. “bicarbonate ion” will work just as well as “hydrogen carbonate ion”). You can also generate problems for calculating their molar masses.

Thanks to Michelle, Seth & Auburn for giving me this idea! Suggestions like theirs have helped me significantly improve since it first launched in 2020, so please keep sending in your feedback and ideas!

Bug fixes & other improvements

As I’ve said in previous newsletters, I keep track of all the suggestions and bug reports that are sent in, and I try to prioritize bug fixes over adding new features, but sometimes it takes me a while to figure out what’s causing a problem or even how to reproduce it so I can track it down. A few of the bugs listed below were very challenging to resolve, so I just wanted to make sure everyone knew how much I appreciate their help and patience! Here’s a list of all the updates since the last newsletter:

Dashboard – these features and bug fixes also apply to

  • new feature: added an expiring progress alert for students at the top of the Dashboard
  • bug fix: assignments for “All Classes” weren’t showing up on the Assignments page for colleagues (thanks, Bill!)
  • bug fix: overriding a student answer that was marked as “incorrect” would sometimes count for multiple points (thanks, Jason!)
  • bug fix: PHP notices were showing up in the production version of the Dashboard (thanks again, Jason!)


  • bug fix: an exam section would be inaccessible to students if they previously completed the assignment that section was based on and “Allow multiple attempts” was turned off (thanks, Cynthia!)

All Quizzes

  • improvement: tweaked the design of answer pages on all quizzes so they have similar column widths
  • bug fix: students were sometimes being prompted to finish an assignment for “All Classes” that was from a different teacher at their school (thanks, Lauren and Maggie!)

Acid-Base Equilibrium Quiz

  • bug fix: the correct answer for [H+] problems was incorrectly calculated as 1.00 for multiple choice questions, resulting in no correct options (thanks, Susan!)
  • bug fix: sometimes the correct multiple choice option for the dissociation constant value was marked as incorrect due to rounding

Balancing, Identifying & Predicting Chemical Equations Quiz

  • bug fix: diatomic gases were being truncated in multiple choice options for prediction questions (thanks, Matthew!)

Chemical Equilibrium Quiz

  • new feature: added “Avoid converting between Kc and Kc when calculating equilibrium constants” option (thanks, Lan!)
  • bug fix: solution setups for problems requiring conversion between Kp and Kc were missing some steps (thanks again, Lan!)

Kinetics & Rate Laws Quiz

  • bug fix: incorrect values were being used in solution setups for rate law problems with data tables (thanks, Mary Ann!)

Lewis Dot Structures Quiz

  • new feature: added Lewis structures for 227 molecules and polyatomic ions (thanks, Mike and Mags!)

Naming Compounds & Calculating Molar Masses Quiz

  • new feature: added an option to select polyatomic ions (thanks, Michelle, Seth & Auburn!)
  • bug fix: choosing ionic compounds with common polyatomic ions excluded fixed-charge nonmetals like chlorine (thanks, Drew!)
  • bug fix: answers for alternate names without a space between the positive ion and parentheses were erroneously being marked as incorrect

Other improvements

  • improvement: tweaked site security settings so that a school is less likely to be accidentally blocked by the firewall (thanks, Debbie!)

Please keep submitting your bug reports and suggestions! has improved significantly over the past three and a half years thanks to all the teachers and students who have gotten in touch with me, so thank you all again for your support.

Site licenses for the Dashboard

Site licenses for the Dashboard allow teachers to create assignments for their students and track their progress. Thanks to the many schools, colleges, universities and tutors who have renewed or purchased a site license for this school year! Site licenses are how I pay for web hosting and site security as well as the software I use to write and maintain the quizzes, and it keeps the website ad-free.

If you’d like to purchase a 12-month site license or renew your existing license, you can pay in one of the following ways:

    • credit card through Square (the most popular option)
    • school purchase order (contact me for a sales quote – I’m also happy to fill out any paperwork required by your institution or state, and I’ve already completed student privacy paperwork for states such as CA, IL, WI, and the six state MA-ME-NH-NY-RI-VT Student Data Privacy Consortium)

Additional schools in the same district can purchase an add-on license for 50% off at just US$35 per school. If you also teach physics or you have a colleague who does, you can bundle a site license for the Dashboard for just US$35 more! Please contact me if you have any questions about how to purchase a site license.

Finally, if you teach in a high poverty public school or district (at least 50% of your students on free/reduced lunch or designated “economically disadvantaged”), please send me a link to the supporting documentation and you’ll get a free site license for the Dashboard forever (, too!). I want to continue to be a useful resource for as many students as possible.

Help me share with the world!

If you like using, there are three quick and easy things that you can do to help me promote the site!

  • Add your school to the list of supporters on the About page! Simply go to the Dashboard, click on “Your Info” in the top menu bar, activate the box next to “Display School on“, and click the “Update Your Info” button.
  • Tell another Chemistry teacher about and encourage them to try out the Dashboard!
  • Follow @ChemQuizDotNet on X (formerly Twitter), Facebook and Threads and share my updates with your fellow Chemistry teachers!

I’m not sure how many of you are in the path of the Great American Eclipse next month on April 8th, but it’s passing through my town (Kent, Ohio) and I’m super excited about it! When the partial solar eclipse happened back in 2017, our district bought eclipse glasses for all of the students and staff, and then we took all the 6-12th graders out to the football stadium to watch it happen (I was also the MC for the event – I wrote a script and everything 😂). Those 6th graders from 2017 are now seniors, so it’s pretty cool that they’ll be able to experience two solar eclipses in such a short span of time!

However, because this will be a total solar eclipse, we’ve been warned by local authorities to start stocking up on food, water, fuel and batteries at least a week before the event because we’re going to be overrun with “eclipse tourists”! Hotels in the area have sold out, school districts in the counties along the path have already canceled for that day, and we’ve been told to expect 6-8 hour delays on roads and highways. 😱 That’s all very concerning, but I’m most worried about the Spring weather in northeast Ohio, which is often overcast and can be very mercurial. I don’t want to have to wait until 2044 to see the next one!

As always, thank you for your continued support of! I hope that the school year has gone well for you so far and that you’re able to take a restful and relaxing break soon. Please feel free to reach out to me via the Contact form or at if you have any questions, suggestions or concerns. Take care!