an online tool that visualizes the structure of an atom, as consisting of protons, neutrons, electrons & their orbitals, from the relatively simple Hydrogen (H) to somewhat more complex Ununoctium (Uuo).

an additional diagram illustrates the relative scale of the distance between a proton & an electron of an hydrogen atom, as horizontally scrollable pixels on the screen.

[link: keithcom.com & keithcom.com (relative atom scale)]