There is a term in physics and somewhat chemistry, the “island of stability”. Essentially as atoms get bigger, they tend to be less stable. That is, they are radioactive and tend to decay into smaller atoms.
Except there is a suspicion that when they are large enough, they might get to be stable again. Here’s a map of this island, with mistakes, from a Wikipedian user:
The mistakes in question are of the proton and neutron numbers, so don’t use this on an exam.
Having said that, it is a beautiful illustration of the concept and the naming conceit. Anyone can see why it is an “island” in speech. The current image is more scholarly, but less attractive.