I tried to model a single atom using mass distribution across

I want to model a single atom, I've built a sphere. And I need to know how to distribute density inside the sphere?

Is there any formula to do that?

[Bjorn Gustavsson]

What are you trying to model? All the mass (electron mass is something like 1/1836 of a proton mass) are in the nucleus.

[Andrian Mirza]

This is the main idea. I plotted a sphere, and want to know if I can make it a solid and to distribute the mass accordingly.

The sphere is the atom itself actually. I did not mention that.

[Bjorn Gustavsson]

This is not how atoms "look". You cannot distribute the mass evenly in any sphere larger than the nucleus. For most purposes I guess you can model the atom as having the mass uniformly distributed in the nucleus, but that is tiny compared to even the radial average of the lowest electron-wavefunctions. Have you understood the structure of the atom, with a nucleus and electrons as "wave-functions"?

WHAT are you trying to model?