Okay, so I understand that the number of protons in an atom defines the element. But why are there only 118 of them? Can’t we keep on adding protons to an atom to create new elements?

Question

EDIT: Thanks for all the responses!

In: 3337

Answer 1

To add onto why it’s so hard…

Only one isotope of element 118 has been experimentally observed – Oganesson 294. It has a (predicted) half-life under 1 millisecond. So, after a tenth of a second, that’s over a hundred half-lives. If we start out with 8×10^31 atoms, we will have just one (on average) after just a tenth of a second – assuming there’s no chain reactions. For reference, Avogadro’s constant (the number of atoms in a mole) is about 6×10^23, and a kilogram of Oganesson has around 3.3-3.4 mol in every kilogram. We don’t really have a solid value because we have only detected five or six atoms of the stuff.

It may be the case that later elements on row eight are more stable. It’s even theorised that more stable forms of Oganesson exist… But that’s what we are dealing with here. Elements so unstable that even the stable ones evaporate into nothing in a matter of mere seconds.