What would the theoretical Element 184 be like?

Reading today about the confirmed discovery of element 117. Which lead me to the hypothesis of the Island if Stability around Element 184.

Just curious if there is any conjecture about what such an element would be like in terms of physical properties, and if it did indeed have a long half life what a substance made from that element might be like?

I think you will find that this “island of stability” is only relative stability. The stuff is still going to have too short a half-life for it to be practical to make anything from it, or do any significant chemistry. I suppose its approximate properties could be deduced from its position in the periodic table.

I am curious about the use of the word discovery when making all these elements. Do physicists believe that if they can make a nucleus of element 117, there are others out there in the universe elsewhere? I suppose that if they do, using discovery would be OK. However, these big elements all have really short half-lives, which to me suggests synthesized would be a better term than discovered, since they were made in a lab.

My guess is that it would be heavy and radioactive.

Regarding synthesized vs. discovered – reasonable semantic argument, but I bet we’d hear them say “discovered” simply due to habit.

Chemically (assuming you can find enough of it to do a chemical reaction), it would behave like whatever elements are directly above it in the periodic table. By my quick count (and assuming there are equivalents to the Lanthanides as elements get heavier), that would put it the same column as the Noble Gases, which means it’d be nearly unreactive. It may be too heavy to be a gas, however.

It would have 184 protons and 184 neutrons in the nucleus. Probably 184 or so electrons. Probably a very short half-life compared to what us muggles consider to be a stable element.

It would almost certainly have many more than 184 neutrons. The heaviest elements now have 50% to 60% more neutrons than protons for their most stable isotopes. And when these things are created they’re mostly just nuclei. Though could one hang around long enough to be unionized, it would have exactly 184 electrons.

Yes, definitely. I see the Wikipedia Island of stability article mention an expected at proton number 164, and the total atomic weight is expected to be 482 - twice as many neutrons as protons. (And perhaps this is the element the OP meant to ask about? I don’t see any mention of 184.)

Revisiting the idea of “relative stability” - this element at 164 is expected to have a half-life of around 2.6 seconds (equal to Flerovium at 114). While that’s remarkably high for its size, you’re not going to be building anything out of it.

(Flerovium?! Yes, apparently element 114 got a name while I wasn’t looking.


But which elements would be likely to approach it to join a union?

[spoiler]Of course, there is an ambiguity as to what word is meant by the same spelling. Un-ionized? Or union-ized? There is at least one other pair of words like this, not counting the present and past/past perfect form of a verb to describe waht you are doing right now.

But this is my favorite.

Good analysis of neutron/proton ratio, BTW.[/spoiler]

Is there any purpose to the creation of these elements?

I’m not asking if there’s any PRACTICAL purpose - I’d be fine with pure science for knowledge’s sake. But from what I understand, it doesn’t seem to be even that. They create a few atoms that exist for less than a second, and then declare what they “expect” the physical properties of the new element to have been - something they could have done, and probably even did, before they had actually created it. Has the actual creation of these elements led to any new knowledge other than “it was possible to create a few atoms of them, however briefly”?

My guess is that they use “discovered” because although the element itself was made and not found, until now they could only guess about its properties. In other words, the element was synthesized, and so now they can discover its properties.

At the very least, observing the half-lives has lead us to defining groups of stable atoms, which has in turn provided support for the idea that protons and neutrons fill “shells” the same way electrons do. Full shells are more stable, just like with electrons.

You’re right that we’re mostly just confirming what we already predicted, but there is some value to that. If we all just took a theory as a given because it worked for elements up to 100, you’d hate to miss a totally different and unexpected behavior that appears at 101. It’s like Newtonian physics vs Relativity. Newtonian equations are fine for 99% of everyday calculations, but when you get to certain extremes, it gets the answers totally wrong.

Thanks for the correction.

Actinium perhaps, or one of those lefties from Berkelium.



I’d have no problem with that, but do the atoms in question last long enough to actually experiment to confirm or contradict those predictions?

Dammit, where did my 164-ium coffee mug go? I set here on my desk just before the meeting …

It must be with my unobtanium mug. Oh well. There’s always another NPR fund drive.

If nothing else, you can measure the lifespan and what it decays into. There’s still a lot we don’t know about the strong nuclear force, and these experiments are one of the ways we learn.

I probably got the terminology wrong. I just went back and looked and 184 is the number of neutrons of the theoretical element. :o

Then it’s probably actually 118 or Uuo. I hadn’t realized until I checked Wiki that it is predicted to be a solid and not a gas.

There are theoretical elements that are in the theoretical g-block of orbitals. (The lanthanides and the actinides are in the f-block). For the other elements mentioned in this thread, 164 is in Group 12 below Zn, Cd, Hg, and Cn and 184 is somewhere weird in the eka-superactinides and I can’t figure out from the periodic table on Wiki how that would line up with the other groups.