||Hydrogen-1 is the most common isotope of hydrogen, with one proton and one electron, depicted with the electron orbiting the central proton. It is also occasionally known as protium.
||Deuterium is the second most common isotope of hydrogen, with one electron and both a neutron and proton in its nucleus. About one of every 6,760 hydrogen atoms in seawater is deuterium. Its chemical symbol is D, or 2H, and it's also called heavy hydrogen or hydrogen-2.
||Tritium is the third most common isotope of hydrogen, with an electron orbiting a nucleus of one proton and two neutrons to give it an atomic mass of about three daltons. It is radioactive with a half-life of about twelve years and is very rare (but not as rare as unbound "instant hydrogen" neutrons). It can also be designated as hydrogen-3, with the symbol T or, more often, 3H.
||Only in the lab
||This is a free electron orbiting around nothing. Following the naming of the heavier hydrogen isotopes, where a prefix designating the number of nucleons is followed by the suffix "-ium", the lack of a nucleus is designated here by the absence of a prefix. A free electron will not circle around nothing but will react to electromagnetic fields. A Penning trap can confine electrons to move in circles.
||This fictional form consists of a proton, electron and neutron orbiting around nothing, with the appearance of all rotating as if on a wheel rim. The neutron could bind to the proton, but will more likely elastically scatter away.
|Instant hydrogen (ready in 15 minutes)
||Yes, but rare
||This is just a single neutron. An unbound neutron will decay into a proton, an electron and an antineutrino after a mean lifetime of just under fifteen minutes. While the free proton is technically a positive hydrogen ion, the emitted proton and electron will only form into an atom together about four times in a million. The name is likely a reference to "instant" food, such as noodles, which are reduced for convenience and can be quickly reconstituted when required.
|Hydrogen (maximum strength)
||This fictional isotope consists of an electron, a proton and what appear to be at least 15 neutrons. The heaviest hydrogen isotope known at present is 7H, with six neutrons. All isotopes heavier than 3H decay almost immediately, most likely by dripping neutrons and emitting a large amount of energy. "Maximum strength" may be a reference to over-the-counter medicines that contain the largest permitted quantity of active ingredients.
|Oops, All Neutrons
||This fictional form consists of four neutrons, with one orbiting around a group of three. As the existence of tetraneutrons is still uncertain, their possible configurations are unknown but the depicted configuration is very unlikely given the characteristics of the fundamental forces. The name is probably a reference to an American breakfast cereal called Oops! All Berries, which has also been referenced in 2256.
This shows as a 404 on xkcd.com but in my RSS feed i can see the comic
- Works for me. 126.96.36.199 02:25, 3 January 2023 (UTC)
- works for me now too but it didnt before
- It works on m.xkcd.com and on the homepage of xckd, but the direct link gives me a 404. Various services such as the Wayback Machine show it as loading though. Could be a bad cache on some service. 188.8.131.52 02:37, 3 January 2023 (UTC)
Could someone add an explanation of Nydnonen? I don't get it and it's google proof 184.108.40.206 05:04, 3 January 2023 (UTC)Benzodiakanine
- Nothing. Was hopeful about List of Greek and Latin roots in English/N but nope. Tried stemming on all the Wiktionaries too. 220.127.116.11 05:28, 3 January 2023 (UTC)
- Kudos to whomever figured it out, lol! 18.104.22.168 08:02, 3 January 2023 (UTC)
- Seems someone already did. There are four N's in that word replacing three of the consonant in Hydrogen so there are now four Ns one for each of the four neutrons in Nydnonen. ;-) --Kynde (talk) 08:10, 3 January 2023 (UTC)
Are these to scale? I recently read that the Helium is smaller in terms of measured atomic radius than the Hydrogen. Possibly this is true of Deuterium as well? 22.214.171.124 06:50, 3 January 2023 (UTC)
- They are almost the same size but it depends on temperature: https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200800063 126.96.36.199 08:00, 3 January 2023 (UTC)
- Is the reason Helium is smaller not that there are double the positive charge which the electrons thus orbit in a lower orbit (I know this is not the correct in reality with the orbit). But if true then Deuterium would not have this effect as it is not the weight but the charge that changes the orbit. And Deuterium has the same charge as Hydrogen as does Tritium. --Kynde (talk) 08:10, 3 January 2023 (UTC)
- Kynde is right, it is essentially the charge of the nucleus that determines orbital size, not its mass (which is always thousands of times larger than the mass of the electron). Nuclear mass has only very small effects on the electron orbitals. The most prominent effect probably would be that with a heavier nucleus, the center of mass of the atom would shift a little bit closer to the center of the nucleus (or, in other words, the reduced mass of the electron would increase a little bit), where the "little bit" is on the order of less than 10^-3. Other effects like nuclear size (distribution of the positive charge) or gravitation would be even much smaller.
Note that the paper cited above does not deal with the size of atoms. Instead, it describes the effect of temperature on the molecular volume of benzene (C6H6) versus deuterated benzene (C6D6). This makes sense, since the apparent volume of a molecule depends on, among others, the amplitudes of intramolecular vibrations, which in turn depend on bond strength, mean energy (temperature), and atomic mass (hence the isotope effect). However, temperature does not affect the size of an atom. In fact, for a single atom, "temperature" has no meaning at all. --188.8.131.52 13:08, 4 January 2023 (UTC)
Is "oops all neutrons" distinct from Neutronium, which is also all neutrons? 184.108.40.206 07:38, 3 January 2023 (UTC)
- Neutronium is ultra-dense and bound by gravity, with a minimum of about 1.2x1058 neutrons in a 40 kilometer diameter sphere. 220.127.116.11 08:00, 3 January 2023 (UTC)
- Well actually a neutron star is only 10 km in radius (20 km in diameter) according to Wikipedia. And it is 1057 neutrons acording to this lecture on Neutron Stars. Neutronium was actually used as a name for neutrons without protons and suggested to be placed as number 0 on the periodical table. But is has also been used as a name for the matter in the center of neutron stars, but usually not in scientific papers! There it is called degenerate matter. The wiki article mentions how a single neutron decays to proton/electron/neutrino in 15 minutes. It also mentions that two neutrons could form for very short periods in nuclear decay. An then mentions that more than two neutrons together is not likely to exist. Specifically mentioning the three from Randall's Oops particle as not being stable for even the shortest of times. Of course a neutron would also not be able to orbit a group of neutrons. But even the three at the center is impossible. More neutrons together would be isotopes of number 0 element... --Kynde (talk) 08:22, 3 January 2023 (UTC)
- My bad memory; thanks. 18.104.22.168 05:08, 4 January 2023 (UTC)
I think "Maximum Strength" is a reference to medicines marketed as such - in particular brands of Ibuprofen "Maximum Strength Tablets". --22.214.171.124 14:59, 3 January 2023 (UTC)
- Yes - typically meaning that it contains far more of whatever its active ingredient is than is necessary to be efficacious.126.96.36.199 15:54, 3 January 2023 (UTC)
Considering that Deuterium is derived from Greek and Tritium works in both Greek and Latin, wouldn't the correct name for ⁴H be Tetartium?
- Tetrium maybe? Tetraium? 188.8.131.52 05:08, 4 January 2023 (UTC)
Is it just me or have the recaptchas gotten much more difficult over the past week, to the point of ambiguous or indiscernibly blurred images and frequently rejecting correct responses (i.e. "please try again" in red)? Granted, I'm not saying this behavior makes it any less valid as a captcha, but it's a little surprising to always get several-step challenges lately. 184.108.40.206 05:08, 4 January 2023 (UTC)
- Captchas are in a continual arms race with bot writers, and wax and wane in difficulty as new attacks and counter-measures are deployed. ReCAPTCHA occasionally becomes more lengthy when they refresh their image library; we may be experiencing that. It sure doesn't seem to be slowing down the creation of new phantom usernames -- does registration even have the captcha? 220.127.116.11 07:43, 4 January 2023 (UTC)
- Firstly yes, and that might be the problem, because ReCAPCHA is still quite mild on other sites. Whomever is automating username registration here (which has been going on at least five years) may have fallen prey to a new countermeasure increasing their failure rate and making our site's angry. 18.104.22.168 12:21, 4 January 2023 (UTC)
- As a habitual IP of long-standing, I had not had a reCAPTCHA for soooo long, I realised, when I suddenly had one the other day.
- It didn't like my first and second answers (traffic lights and crosswalks? ...typical 'on this single image' ones with edge-conditions that I never know what it's fully asking for/used to getting as an answer, inclusive or not of the poles/backdrop surround to the actual lights, tiles with just a sliver of painted road shrface, etc) before passing me on an "of these images" (all with buses/tractors? ...better than the time when it had two tractors, but clearly had been trained by others that its traditional third item counted as a tractor even though I knew it was something like a road-building scraper/planer thing) which worked.
- But, so far at least, that was the only one (set) I got. And I had noted mysterious 2+hour gaps in silly-name new account creations, at times (notable due to the gap between the new account history and the midnight cutoff/restart in the Recent Changes compilation) - it would be nice to imagine that they were being blocked more. Though I think an immediate account-creation failure probably redoubles their next effort to create an account of some kind. (It's only the failure to use the account, subsequently, that throttles back the obvious presence of such scripted interventions. Perhaps actually by spending time hammering the server but without any visible results as far as reaches my own limited awareness of server activity via the changelog.)
- As described, it's an arms race. And while I know I don't hanker back to the days of every. single. post. requiring a reCAPTCHA (sequence) from me, that'd be much nicer than an unusable platform due to scriptspamming. Currently seems to be about right, IMO, especially with theusafBOT's handy high-speed autoreverts on those spams that are (somehow, by using a wetware processor?) momentarily getting through on Unreliable Connection and the others... 22.214.171.124 15:19, 4 January 2023 (UTC)
Re "ium": Shouldn't we try to keep the explanation short and to the point? This comic is about "isotopes", i.e. about different options of how to construct a single atom (or atom-like entity). IMO, there is no need to include many-body effects in a set of multiple electrons ("Fermi velocity" or "electron degeneracy pressure"); just as there is no need to discuss, say, the kinetic theory of gases made up of these isotopes, or how they would be able to form fluids or solids. It is good to see that people who contribute here know about these effects, but I think that the explanation does not benefit from extending the discussion too far beyond the subject of a given comic. If anything, it might be worthwhile to include a reference to ion traps - especially since in a Penning trap electrons actually go in circulating orbits (although not exactly circular). --126.96.36.199 11:56, 4 January 2023 (UTC)
- Go for it. We all agree to have our "writing to be edited mercilessly" in the fine print just below the Summary. Editing on whims is good because if someone else liked something earlier they will just merge it back in somehow. 188.8.131.52 12:21, 4 January 2023 (UTC)
I love the administratium joke, but adding more jokes in the description seems antithetical to the purpose of this website :) 184.108.40.206 21:30, 4 January 2023 (UTC)
- +1, same here. But if the joke's too good to delete, it might be moved to the trivia section. Also, a proper reference would be in order, as the joke's been around the web since 1989 at least --220.127.116.11 22:07, 4 January 2023 (UTC)
One thing about this cartoon strikes me as impressive. "Hydrogen, maximum strength" is about 5-10 % protons. Bulk nuclear matter, which is what makes up most of the body of a neutron star, has a neutron/proton ratio between 10 and 20 (probably close to the higher value). Hydrogen (maximum strength) is what holds up a neutron star, and that qualifies as pretty strong in anybody's book. And, while on the topic, there is no such thing as "neutronium". The cores of neutron stars are covered by a "nilium ocean" of free neutrons - but that term applies to bulk properties of the ocean. Go to the microscopic picture, and its just free neutrons; it is not a substance in its own right.
A second point, if I may. An electron can orbit an empty place quite easily if you put it in a magnetic field - but there is another possibility. Dark matter exerts gravitational attraction on electrons. Given enough room, an electron will orbit dark matter. Perhaps "ium" should be called "darkium". -- Adeblanc (talk) 14:57, 2 February 2023 (please sign your comments with ~~~~)