This file is from Wikimedia Commons and may be used by other projects.
The description on its file description page there is shown below.
Summary
DescriptionAtom Diagram.svg
English: Diagram of an idealized Lithiumatom, primarily useful to illustrate the nucleus of an atom. This sort of design is scientifically inaccurate in many important respects, but serves as a powerful mandala of the nuclear age.
Inspired by drawing from User:Fastfission, recreated by User:AG Caesar in vector/svg format.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the licence, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible licence as the original.