could definitely be
+ I liked the various styles. Specially the simple +/-s.
---- Kinda overly limited.
--- I distinctly remember that elements have a certain number of neutrons - it's not just the protons/electron that make it what it is.
-- centre button, which took us to the never-ending stream of code, was annoying.
????? A reviewer below suggested having protons/neutrons only draggable to the centre, whilst electrons should gon on the outside. That would be rather cool, making it more visually intuitive.
??? You could easily make the electrons spin round by making them mcs, maybe instead of dragging, we'd toggle a number... you could either have an mc with frames for each number of electrons, or you could duplicate the mcs at a random rotation each time, centred on the neucleus. That would be kinda impressive-looking.
Always good to have some new styles of content.
Needs more work done to it, but it could definitely be a cool little application/thing.
Keep at it!