In physics, atom is the most basic form of the chemical elements, primarily consists of a nucleus made of protons and neutrons, and were typically surrounded by electrons.
This tag can be apply to the "basic" visualization of an atom, such as a sphere surrounded by ring(s) with several electrons orbiting around it. Do not tag atom when the character is simply manifesting a simple energy ball with no distinctive shape (such as Reiuji Utsuho's "atomic ball").