The largest possible atomic nucleus theoretically is Oganesson-342, which contain a total of 342 nucleons, has 118 proton and 224 neutron.
The largest atomic nucleus forms 7x7x7 cube, with one empty center unit, it has total 7x7x7-1=342 nucleon
The Largest Atomic Nucleus - 3D WebGL
Front View
Back View
Layered Front View
Layered Back View
The Top Layer
with all the spin up proton 7x7=49
four conner with one s proton, three p proton, and two f proton
Top Layer Front View
There are one spin up s proton and one spin down p proton in the front view
Top Layer Back View
There are two spin up p proton and two spin up f proton in the back view of the top layer
The Second Layer
with all spin up neutron 7x7=49
The Third Layer
with 8 spin up d proton and all other spin up neutron
The Fourth Layer
it is also the middle layer of the atomic nucleus, with 4 spin up d proton, one unit empty center space, all other neutron
The Fifth Layer
with 8 spin up d proton and all spin down neutrons except one spin up center neutron
The Sixth Layer
with all spin down neutron except one spin up center neutron, with total 7x7=49 neutron
The Bottom Layer
with all spin down proton except one spin up center proton, with total 7x7=49 proton,
Bottom Layer Front View
four conner with one s proton, three p proton
There are one spin down s proton and one spin down p proton in the back view
Bottom Layer Back View
There are two spin down p proton and two spin down f proton in the back view of the bottom layer