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The ratio of neutrons to protons as atomic number increases is not a linear relation.
For example, helium is typically assumed to have 2 electrons and two protons, and in most cases 2 neutrons, but there are species of helium with 1 neutron,
Meanwhile hydrogen has 1 proton 1 electron and 0 protons, but species of hydrogen we call deuterium, and tritium have 1 or 2 neutrons. Anyhow, as you go up the periodic table, which numbers each element by its number of protons, the amount of neutrons necessary to stabilize the atom varies. After 118 the correct combination of protons to neutrons which would cause the atom to exist in the band of stability becomes increasingly vague and the math of how each combination of proton to neutron coupling would decay (upwards or downwards with alpha beta or gamma decay) is unknown as well.