In chemistry and physics, an atom (Greek ?τομος or átomos meaning "the smallest indivisible particle of matter, i.e. something that cannot be divided") is the smallest particle still characterizing a chemical element.

The atom in the Reciprocal System is different from conventional physics in that it is composed solely of a single, compound motion, not protons and neutrons lumped together into a nucleus and electron cloud.

Atomic properties are not solely due to the compound motion of the atom. The counterspatial fields generated by atomic motion allow the capture of other particles, such as electrons and neutrinos, which account for much of the currently observed behavior of conventional physics (though technically not part of the atom, itself).

The mass of the RS atom is twice its atomic number. Isotopes of that mass occur through the capture of material electron neutrinos, adding 1 AMU per capture.

RS atoms have no electrons as part of their atomic motion. They do have a 1-dimensional rotational component that has "electron" properties. Also, electrons can be captured by the atomic rotations under certain conditions, which result in electron orbitals.

Atomic valences (oxidation states) are just the speeds of the motions making up the atom. These speeds can be 2-dimensional (magnetic) or 1-dimensional (electric).