Diagram of an atom of helium: blue - spherical orbitals of electrons (size around 32-140 pm), red - protons, grey - neutrons (size of nucleus is around 0.001 pm).
The blue electron orbitals extend beyond the size of the picture, and the small dot denoting the nucleus at the centre is not drawn to scale (it would be less than 1/100 of a single pixel).
The values of dimensions are specified after:
atom_helium_magnetica.jpg
You are permitted and indeed encouraged to use this image freely, for any legal purpose including commercial, and with any modifications (the permission is hereby given, so there is no need to ask for it explicitly again), but you MUST always give the following credits:
S. Zurek, Encyclopedia Magnetica, CC-BY-4.0
We would appreciate if you let us know of any use: info@e-magnetica.pl