Hello good people,
What are the current scientific theories regarding the ultimate disposition of the periodic table?A version appears to run to an element, 118, which has been named as Uuo. Unobtanium?
Peter
An “element” is just a distinct number of protons in an atomic nucleus. As such, the table is unlimited in size. However, large nuclei are (generally speaking) unstable, and will decay in very, very short amounts of time to lower numbered elements.
There is some potential for “islands of stability” later in the table, where particular arrangements of nucleic particles might allow for stable atoms, but no one’s proven it one way or the other yet.
Wikipedia has a cool article on that island of stability^^^, with pics.
Stability, in this context, is a relative term. Elements in the expected “island of stability”, if they can be made, are still almost certain to be highly unstable, and to decay into lighter elements fairly quickly, almost certainly well before their chemical properties (which is what the Periodic Table is really about) can be measured, much less exploited. For all practical purposes, the Periodic Table is complete as it stands, and will not change.
Unfortunately, no. It’s actually Ununoctium, a placeholder name until its discovery can be confirmed. The prefixes indicate un-un-oct, or one-one-eight, for its atomic number.
Element 118 is called ununoctium because the folks who decide element names decided to name stuff using the latin for it’s atomic weight, since naming it after the discoverer was deemed excessively narcissistic and resulted in names that weren’t universally pronounceable. Latin (along with international symbols and software icons) has the benefit of being foreign to everybody.
Not to mention the feuds between western and soviet teams over the naming rights for previous high-Z elements. Latin-ish names are apolitical.
It seems like 118 has been the top dog for a while, and synthesizing new superheavy elements has fallen out of fashion.
However, that’s not its permanent name. That’s a temporary systemic name pending confirmation of the discovery, at which time the discoverers will be able to give it a permanent name.
It’s generally considered tacky at best to name something after yourself. Naming it after your university, though, or your place of residence (country, state, city, etc.), is acceptable, as is naming it after someone admired and dead.
As a Trekker of long standing (that is to say that I have been standing a long time and am a bit tired) it may be of some amusement to a few to view this periodic table of the elemts from the Star Trek Universe:
Periodic Table According to Star Trek
Note that Element 118 is known as Zienite in this table. More information may be found here: http://misc.thefullwiki.org/Zienite
It also appears that Corbomite is the heaviest element known at the time of this chart’s last update.
I know all of this must be factual as it was found using Google on The Internet.
Also, several of the earlier elements were named after characters in DC Comics’ Metal Men series.
How does a Star Trek Periodic table not have Latinum? Sloppy.
Perhaps it is a compound?
Or the table was last updated prior to contact with the Ferengi?
Or, just maybe, it is all just… naaaahhh… that’s just crazy.
What’s really sloppy is to talk about naturally occurring ores that contain element 118 - which has a half-life of 0.89 milliseconds.
Timewinder now that does fascinate me, I assume we are discussing concepts not theorems?
‘There is some potential for “islands of stability” later in the table, where particular arrangements of nucleic particles might allow for stable atoms, but no one’s proven it one way or the other yet.’ cf.
Thank Og for the Open University, I feel another degree coming on, highly recommended.
‘Islands of stability’, I don’t mean to disparage you but ‘things we know, things we don’t know’ ?
Damn Chemists will annul Og, please.
Rambling Pete
The islands of stability are mathematically predicted, according to mathematical laws which govern the relevant interactions. The physics isn’t perfectly understood, and the calculations aren’t all that straightforward, so there’s still some uncertainty on points like just how long “island elements” should last before decaying, but we’re pretty confident about the existence of the islands, at least, and that they would last longer than the elements on either side.
I feel like I once heard some discussion somewhere of there being a maximum theoretical size for elements, based on the fundamental forces–basically, it gets so big that some of the forces overcome the other forces and it won’t stick together. I cannot for the life of me actually find any references for this.
Atomic nuclei are held together by the strong nuclear force, which overpowers the electrostatic repulsion between the protons. However, the strong nuclear force has a very limited “reach,” and as the nuclei get bigger, the binding force cannot hold up, making high Z atoms unstable. As noted, islands of stability have been postulated but not seen.
I am reading “The Disappearing Spoon,” by Sam Kean, an excellent non-technical book about the periodic table. He says that relativity places a limit on the size of atoms:
Of course one could argue that a neutron star is really one amazingly large collapsed nucleus with gabazillions of subnuclear particles.
Of course you would have a hard time convincing anyone that it was stable. Its atomic number would be in a state of continual change.
bizzwire, I suspect that’s what I was thinking of. Thanks.