Currently, there is no confirmed experimental evidence for the existence of gravitons, which are hypothetical elementary particles associated with the force of gravity in some theories. Gravitons are part of the framework of quantum gravity, which aims to unify quantum mechanics with general relativity.
In the current understanding of physics, the force of gravity is described by the theory of general relativity, which does not incorporate quantized particles like gravitons. Therefore, the concept of the mass of a graviton and its relationship to the mass of atoms is not well-defined within the scope of our current knowledge.
It's important to note that our understanding of fundamental particles and the nature of gravity is still an active area of research, and future discoveries or advancements in theoretical physics may provide further insights into the nature of gravitons and their possible relationship to the masses of atoms.