To streamline the UI, might I suggest replacing example element (copper) with just the explainers, next to hydrogen [2]... using that elements information (without adding a free-floating copper).
If that doesn't make sense, let me know.
Thanks for being a responsive educator.
[2] perhaps use Beryllium for your example/explainer -- because then you can explain the electron orbitals too ..?
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Replace the topbar (color==atomic class) location to between Group II & III elements (e.g. whitespace between Be B); does not need to be explained on example element text.
>> <https://i.imgur.com/hswLkAt.png>
Beryllium finally has a use (as explanatory element)! The American Chemical Society rejoices...
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Text to add:
>Electron configuration
>Density (with units)
>State of matter @STP (cannot remember?! something like 27°C at one atmosphere — embarassed to not remember, I used to teach this stuff!)
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Lastly, your current webpage title/header is:
>>Interactive Table | Periodic Table of Elements
When I go to bookmark I reduce this to
>Periodic Table of Elements .org (quick reference)
Be the Referenced namesake to which you've already expressed desire.
I updated the Title to show the .org, but also in the mean time picked up https://periodictableofelements.com so working on that as well to make one the educational and the other to support any costs it might ever have and for any traffic leak I guess.