At some point the element will decay faster than it can exist. There are already subatomic particles that get created on one side of the particle and decay on t

At some point the element will decay faster than it can exist. There are already subatomic particles that get created on one side of the particle and decay on the other, i.e. their lifetime is shorter than that time it takes for light to travel from one side of the particle to the other. Atoms are much bigger than subatomic particles, so they have to live even longer in order to exist.