Talk:Hydrogen

Template:Chemical Element Template:WP1.0 Article changed over to new Wikipedia:WikiProject Elements format by David M. Elementbox converted 16:07, 23 Jun 2005 by Femto (previous revision was that of 15:17, 20 Jun 2005).

User's comment

The specific heat is given for the H2, although 99% of Hydrogen is of the H1 variety. I find it confusing. —The preceding unsigned comment was added by 71.111.47.218 (talk) 16:40, August 23, 2007 (UTC)

Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Hydrogen. Additional text was taken directly from the Elements database 20001107 (via dict.org), Webster's Revised Unabridged Dictionary (1913) (via dict.org) and WordNet (r) 1.7 (via dict.org). Data for the table was obtained from the sources listed on the main page and Wikipedia:WikiProject Elements but was reformatted and converted into SI units.

Archives

/Archive 1: Dec 2004 - Aug 2006

The spin of a hydrogen atom

What is the spin of a single hydrogen atom?

Pretty much the intrinsic spin of its lone electron. There is no angular momentum in the 1s orbital, and the intrinsic spin of the proton is less than 1/600th as much, and doesn't contribute in a significant way (although of course there are energy differences betweeen electron and proton spin alignments-- that's the famous 21 cm microwave line).

The spin of the proton is the same as that of the electron. Its magnetic moment is much smaller.

Shambolic Entity 03:44, 25 January 2007 (UTC)

Hydrogen energy carrier or source of fuel or energy?

gas cost money to make it useable to cars but they hike up the price so it evens out economics but w/e hydrogen is also found in the ground in texas or is that helium i am not sure. I think it is a fuel.Barry White 06:06, 12 September 2006 (UTC)

Liquid hydrogen - Hydrogen merge

I'm proposing the merger because the liquid hydrogen article seems rather short and would probably be totally covered by the contents of this one. After all the liquid form is just a part of the desciption of the full molecule? - Dammit 09:22, 13 September 2006 (UTC)

Strong against merge, The article hydrogen is about hydrogen physics and on a atomic level, where as liquid hydrogen is a fuel. Mion 13:35, 13 September 2006 (UTC)

I vote against the merge. There should be some uniformity in how this is treated in the various articles on elements. Helium, which is a featured article, has Liquid helium broken out as a seperate article. The Liquid nitrogen article on the other hand simply redirects to the Nitrogen article. To me the Helium template makes more sense since I think there is enough material out there to write a full article on Liquid Hydrogen that would otherwise bloat the Hydrogen article. The Liquid Hydrogen article as it is right now is a stub and needs work.Badocter 04:45, 15 September 2006 (UTC)

Since consensus seems against the proposed merge, I've proposed an alternate merge to hydrogen economy, which seems to be where the applications of liquid hydrogen are. - Samsara (talk • contribs) 20:31, 16 September 2006 (UTC)

The arguments where to keep it at its own and give it a go to expand it, so i am against the new proposal, in itself you are right, every hydrogen related article is related to hydrogen economy, but the whole range about hydrogen is 80 to 100 articles and we cant put them all into hydrogen economy.it has to wait until we have a hydrogen portal, and yes you can start one, reg.Mion 00:18, 17 September 2006 (UTC)

Oppose This is a very unsuitable merger. Only part of the liquid hydrogen article relates to the topic, much of it relates to use in rockets. The best idea is to expand the liquid hydrogen article to cover things like its physics, its properties outside of fuel use, its presence in planets such as Jupiter, etc. Walkerma 04:14, 17 September 2006 (UTC)

Merge proposal is withdrawn, case is closed. -:). Mion 11:26, 17 September 2006 (UTC)

"H2" in applications section

I understand that it is important to emphasise whenever one is referring to diatomic hydrogen, but starting a sentence with a summation formula may seem somewhat unprofessional, and more importantly, it leads the line spacing to be upset in some browsers. Can we replace some of those "H2"s with real prose? Thanks. - Samsara (talk • contribs) 19:35, 19 September 2006 (UTC)

Hydrogen Compounds

It is mentioned that hydrogen forms compounds with elements which are more electronegative. If you look at an ordered electronegativity list you will realize that hydrogen bonds with many elements even more electropositive ones. Of course the electronegative elements such as the halogens react with hydrogen much more readily. A few examples of electroposative compounding: Lithium, Calcium, Copper, Silver, Sodium, Potassium, Rubidium, Cesium, Barium, Beryllium, magnesium, Uranium, Gadolinium. I keep going back and forth, searching element-hydrides. Every one I search for has a hydride. Maybe every element has a hydride (?) Scot.parker 20:30, 19 September 2006 (UTC)

I guess that technically, HF, HCl, HI etc. are not hydrides but chlorides, iodides, etc. I'd also have to guess that some of the noble gases may not form stable compounds with hydrogen. - Samsara (talk • contribs) 21:52, 19 September 2006 (UTC)

Corrections

I've corrected the introduction because:

1. Some organic compounds do not contain hydrogen e.g. tetracholoromethane, tetrafluoroethene, PTFE, etc.
2. The Schrodinger equation can be solved for ions of other elements e.g He⁺.

Ewen 08:54, 29 October 2006 (UTC)

In the Applications section, it is noted that Hydrogen is used in preference to any other gas because of its high Thermal Conductivity but I think it should refer to its high Specific Heat Capacity.

If we are in fact talking about Thermal Conductivity then we need to show the value in the List of thermal conductivities. --Graham Proud 10:24, 17 February 2007 (UTC)

Could someone please delete the false statement in "Natural occurrence" "Still, hydrogen is the third most abundant element on Earth." Hydrogen is not the third most abundant element on Earth, it is the fourth, and that's not counting the earth's core (see the article on "Earth"). However, the article that statement is taken from "" is an appropriate reference to use in the later section on "Hydrogen as an energy carrier". Use it as a reference along with the other one at the end of the section. --

There is a grammatical error which is continuous in the discussion and in the article. "an Hydrogen" is correct gramatically; "a Hydrogen" is incorrect. Could someone fix this please Thanks from Luke [13th of May 2007] 2:30PM (AEST)

"An" precedes vowel sounds, the "h" of hydrogen is not silent. Femto 12:16, 13 May 2007 (UTC)

According to A and an, it's "a" for a voiced H (as in hydrogen), unless you're Cockney British and prone to h-dropping. JeramieHicks (talk) 15:13, 9 May 2008 (UTC)

Hindenburg

Reading the wiki article on the Hindenburg disaster, I think it should be pointed out that the cause of the crash has not been 100% decided Mattmore17 19:07, 30 April 2007 (UTC)

The problem is, that the Hindenburg’s "shell" was coated with aluminum powder and iron oxide it help regulate temperature. Today this mixture is used as rocket fuel. If the Hindenburg was filled with (he) it still would have went down in about the same amount of time. Besides hydrogen is about as flammable as gasoline.

Steven Loiselle, Mi

Amount of hydrogen in universum

How much there is hydrogen in universum? I thought that a mount was 90 %. So is 75 % correct?Hannu 11:03, 29 October 2006 (UTC)

If you'd read a little further, you would have noticed the reference given, which is a NASA web page and gives the figure as "three quarters":

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971113i.html

Samsara (talk • contribs) 11:09, 29 October 2006 (UTC)

Yes, but that's by mass. By number of atoms, it's closer to 92%. SBHarris 21:36, 20 December 2006 (UTC)

Electrolysis of water

As the article stands now, there is only a single, two sentence line about electrolysis, and it is all the way down in the Laboratory Syntheses section.

"The electrolysis of water is a simple but expensive method of producing hydrogen. Typically the cathode electrode is made from platinum."

1st of all, this method is not more expensive than digging up fossil fuels, refining them, and then extracting the hydrogen. Currently, the amount of hydroxy gas (H H O or 2H₂O(aq) → 2H₂(g) + O₂(g)) produced from water is very much relative to the set up of the system, the frequency used etc. Various voltages, amperages and frequencies have been used to various degrees of effectiveness. The cost is, of course, relative to the source of electricity used. There are many people who claim to be getting extremely high (even over unity) returns by using the resonant frequency of water. Regardless of whether these claims are true, this method should be given more than a cursory footnote, as it IS very simple.

2nd, produced on a mass scale (an ocean based plant using salt water and solar power for example) this method could be very reasonable, low maintenance, and environmentally friendly. Remember no greenhouse gasses are produced by electrolysis. Oh, and the cathode doesn't have to be platinum... it can be made from stainless steel or a number of other cheaper metals.

I propose mentioning this method and its long and successful history in the opening blurb, and giving Elecrolysis its own section. The article now makes it seem like hydrocracking is the only viable solution... and there are numerous problems with that method; not the least of which being the scarcity and growing expense of hydrocarbon fuels and the pollution associated with using them. The current article paints electrolysis as economically unfeasible and basically dismisses it off hand. —The preceding unsigned comment was added by JahSun (talk • contribs) 11:58, 29 October 2006 (UTC)

It's a good suggestion. Even better, write a small, separate article about the subject and then put a two-paragraph summary into this article, with a link to the more detailed stuff. Make sure you reference everything thoroughly, as this article is now a Featured Article, and hence, we have to keep up the quality. Good suggestions so far, always good to have knowledgeable people on board! Make sure you sign your posts using ~~~~. Use the preview to see what it does. - Samsara (talk • contribs) 12:06, 29 October 2006 (UTC)

Scary statement of the day "Regardless of whether these claims are true, this method should be given more than a cursory footnote, as it IS very simple."

Please dont insert your well-intentions but off-the-mark edits - you are talking to pseudo-science. No the electrode need not be Pt. But greenhouse gases are definitely generated by electrolysis (unless you subscribe to perpetual motion). Electrolysis is powered by electricity that is powered by the burning of fossil fuels (or hydroelectric, nuclear). So you are not going to get more energy out that you put in. Let experts in electrochemistry or electrical engineering make these edits, stick to making suggestions. BTW, hydrocarbons are not scarce - the US just does not like the owners of the reserves. And when we get done with petroleum, there is 1000x more natural gas. --Smokefoot 14:37, 29 October 2006 (UTC)

Electrolysis works. It's been known and used since Faraday, in the 19th century. It is not pseudo-science, and no one is talking about perpetual motion. Obviously electricity must be used, but hydro-electric, solar, wind, tidal, and geo-thermal power (among others) do not generate greenhouse gasses. BTW hydrocarbons are quite a bit more scarce than sea water...

JahSun 15:21, 29 October 2006 (UTC)

yes, but just try to burn that seawater... Yes, Echem generates H2, so what?? One consumes more energy than one inputs! Would be nice to see a scientific reference (a real journal with editors, referees and all that messy stuff) to the "Belona report" - which still looks like a commercial advertisement and may be erased later. --Smokefoot 15:36, 29 October 2006 (UTC)

Not sure what your gripe is. Hydrcracking uses more energy than it generates as well. Are you suggesting people shouldn't know about electrolysis because it obeys the law of conservation of energy? Oh, and you don't burn the sea water... you burn the gas that comes off the sea water after a current has been applied. Many of the methods of generating H₂ mentioned in the article are less efficient than electrolysis or are even purely theoretical. (engineering cyanobaccilus to make hydrogen etc.) JahSun 15:56, 29 October 2006 (UTC)

To be fair to JahSun, I don't think the issue of whether or not eletrolysis is more polluting at the end of the day belongs within the scope of this article at all. We have a separate article on the hydrogen economy, where such issues can find their place. Regards, Samsara (talk • contribs) 16:05, 29 October 2006 (UTC)

thank you Samsara for politely helping me stay in-line. Back to you JahSun: okay maybe electrolysis should be considered for hydrogen production - I leave that call to the financially-guided engineers who run refineries. But neither hydrocracking nor electrolysis is a route to energy, just a reshuffling of our energy content. It was fun sparring with you, best wishes --Smokefoot 16:27, 29 October 2006 (UTC)

Likewise ;-) A good debate is healthy as long as no one takes it personally. All the best... JahSun 16:32, 29 October 2006 (UTC)

Um, people don't use reforming from natural gas to make hydrogen because they're dumb. You could burn natural gas to make heat to boil water to turn turbines to run generators to make electricity to run electrolysis plants. But it's more efficient to simply strip the H2 off the CH4 when you have it. On site H2 made this way is about .32 cents a lb, while electrolytically produced H2 is 3 to 6 times more expensive. [1]. You want to demonstrate electrolysis is neat? Great. Produce hydrogen that way for less than 0.32 cents a lb., or point me to somebody who does. Have at it. SBHarris 23:27, 29 October 2006 (UTC)

The costs you speak of are relative, not fixed things. At the moment you are correct, but neglect to factor in the cost of acquiring the natural gas itself. On site hydrogen reforming may be cheap, but the cost of delivering liquid hydrogen fuel is nearly the same as electrolysis. Furthermore, no one has mentioned the costs of electrolysis using hydro-electric power, tidal, or wind. In an ocean based plant using the sea water (a natural electrolyte which electrolyzes better than pure water) with tidal power, wind, and solar operating in tandem the costs would be VERY cheap. And, the costs must be considered to be amortized over the lifetime of the plant. Solar panels, windmills, and tidal generators have a one-time, fixed cost, and then they run basically for free until repairs become necessary.

Statistics designed to make electrolysis of water look expensive are easy to fabricate. However, you must show where these supposed costs are coming from. In addition, the people who claim that electrolysis of water is as polluting as hydrocracking always assume that the electricity must be generated by the burning of fossil fuels such as coal or natural gas. People conveniently overlook all the factors that don't suit their basic belief or economic interest. Take away the subsidies to the oil and gas industries, factor in the public health costs, add the money spent on security, and the transportation costs to bring it to market... and then see if it is truly cheaper. JahSun 13:08, 2 November 2006 (UTC)

atmospheric hydrogen

Is the amount of hydrogen gas being produced by us, or perhaps of some consequence of climate change at all significant in terms of changing the atmospheric concentration of hydrogen? What is the rate of flow of hydrogen gas from the atmosphere into space (and thus presumably the rate of production of the gas on land/sea)? Does hydrogen gas limit the decomposition of methane and carbon monoxide?

Also, is the absorption/emission spectrum of hydrogen such that it does function as a greenhouse gas? (I ask this regardless of whether the amount of hydrogen in the atmosphere is something that we have any control over.)

Diatomic gases such as Hydrogen gas cannot act as greenhouse gases. In order to absorb infrared radiation (which is a main characteristic of greenhouse gases), the molecule needs to perform asymmetric bending or rocking movements. This is not possible with diatomic compounds.

The other chemical implications of growing amounts of hydrogen gas that is being released into the atmophere have not been explored yet, such as decomposition of methane, carbon monoxide, VOCs, NOx or the ozone layer. —Preceding unsigned comment added by 193.5.216.100 (talk) 11:02, 14 January 2008 (UTC)

Validity of statement of the Hindenburg statement

"(Regardless of the cause of this fire, this was clearly primarily a hydrogen fire since skin of the Zeppelin alone would have taken many hours to burn)." I question this statement greatly. —The preceding unsigned comment was added by 71.98.7.154 (talk) 14:06, 15 May 2007 (UTC).

Hydrogen 5

I read in the book Exempt from Disclosure: The Disturbing Case About the UFO Coverup, 2nd Edition, 2006 by Robert M. Collins, pages 159-161, that an alien energy device (ED) code named "Crystal Rectangle" recovered in June 1947 had been found to contain a sphere containing a hydrogen isotope of four neutrons. This device was reportedly loaned by the TI Advisory Group-6 to NASA and flown onboard and used during three U.S. Space Shuttle missions (STS-92, STS-97, and STS-106). The ED supplied voltage from 9 volts/0.5 amperes to 1100 volts/100 amperes. (Page 163, in op. cit., DIA Scientific Intelligence Report, Top Secret, 19 APR 2001, Top Secret Control NR: 01-04-2231-TI)

Our physicists have bombarded Tritium to make Hydrogen 5 which dissipated in nanoseconds. Perhaps an indirect process may be successful.

[[2]]

In 1939 Hans Bethe calculated the Sun's energy production, which results from the fusion of four hydrogen atoms (each of mass 1.008) into one helium atom (mass 4.0039). No direct fusion is possible, but Bethe showed that the probabilities of the four steps of the "carbon cycle" can account for the energy output. A carbon isotope of mass 12 reacts successively with three hydrogen nuclei (protons) to form the nitrogen isotope of mass 15; energy is produced through the fusion of a fourth hydrogen nucleus to release a helium nucleus (alpha particle) and the original carbon isotope.Larry R. Holmgren 20:41, 12 June 2007 (UTC)

Hydrogen plus oxygen equals an oxyhydrogen flame wich is so strong it can easily slice through steal.

Hydrogen abundance

The articles says this: Still, hydrogen is the third most abundant element on Earth. This does not sound correct to me. Oxygen Silicon Iron would all exceed Hydrogen in quantity. Can someone confirm this? GB 05:12, 25 July 2007 (UTC)

OK I checked the reference myself and it actually says on the earth's surface - not just making up the earth or its crust, so I changed text to say surface. GB 05:18, 25 July 2007 (UTC)

It would be better to pick a different reference that included the earths crust. See abundance of the chemical elements, as well as Abundances of the elements. 199.125.109.79 04:00, 28 September 2007 (UTC)

I would have expected earth's crust, that's what caused me to question this in the first place. If you count the number of atoms it gives hydrogen a big advantage. Graeme Bartlett 21:09, 30 September 2007 (UTC)

This article is missing the ionization energies of hydrogen.

9-12-06 —Preceding unsigned comment added by 70.134.57.120 (talk) 21:58, 12 September 2007 (UTC)

Lightest noble gas

is hydrogen the lightest noble gas? if not which one is ..please someone help me. does anyone one know which gas is put in the declarations case so it dosent fall apart? —Preceding unsigned comment added by 75.31.105.255 (talk) 23:35, 30 September 2007 (UTC)

Hydrogen is not a noble gas, Helium is the lightest noble gas. Graeme Bartlett (talk) 04:47, 22 November 2007 (UTC)

Inconsistency on Hydrogen's atomic radius

I have found that the Hydrogen's atomic radius shown in the atomic properties chart on the right side has a value of 25pm while in the article Atomic_radius#Empirically_measured_atomic_radius it is shown that hydrogen has 75pm of atomic radius (stated by the reference: J.C. Slater, J. Chem. Phys. 1964, 41, 3199).

It would be great if anyone could verify and edit the information (I am not allowed to edit such data). I do not know how to notify this and I thought to post it in the discussion page. --18:30, 22 October 2007 (UTC)Tripplez

Oxygen Article Says Its The Third Most Abundant And The Hydrogen Article Says Its The Third Most Abundant!!!!!!!!

You have got to look at how it is counted and where. Hydrogen was counted as just the surface, and that gives the oceans a big influence. If you count atoms hydrogen gets ahead because it is light. Oxygen is the most abundant element in the earth's crust. Hydrogen is the most abundant element in the universe. Graeme Bartlett (talk) 04:50, 22 November 2007 (UTC)

Page is protected? / solubility not important?

The small lock icon is not very obvious to a casual user, I had to study Template:Pp-semi-vandalism to figure out what is going on, but anyway; to the point: The "not" in the section "Chemistry" seems out of place.

"The solubility and characteristics of hydrogen with various metals are not very important in metallurgy (as many metals can suffer hydrogen embrittlement) and in developing safe ways to store it for use as a fuel."

Doesn't the sentence go on to say why is IS important? Perhaps someone someone who can edit the page could consider changing it? 71.212.26.92 (talk) 03:21, 30 November 2007 (UTC)

That bit of vandalism was never corrected. It's fixed now. Thanks. --Squids'and'Chips 04:59, 30 November 2007 (UTC)

Enthalpy

"The enthalpy of combustion for hydrogen is – 286 kJ/mol"

I put a cite tag on this. It's been a while since I took Chemistry, but here are some references:

• http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/electrol.html
  • http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/therprop.html#c1
  • at 298K and 1 atmosphere pressure
  • Enthalpy of −285.83 kJ/mol for liquid water
  • Enthalpy of −241.82 kJ/mol for water vapor
• [3]
  • "enthalpy of combustion of hydrogen of −241.8 kJ/mol H₂."

Not sure what this means, but now we at least have refs. — Omegatron 17:45, 26 January 2008 (UTC)

also Talk:Oxyhydrogen#Enthalpy and Oxy-fuel_welding_and_cutting#Hydrogen — Omegatron 22:07, 26 January 2008 (UTC)

Hydrogen combustion

Possibly this is a dumb question, as it's been decades since I took college chemistry. If I have two moles of H₂ and one mole of O₂, for a total of 3 moles, that should burn to produce 572 kJ. Right? So shouldn't the energy produced in the "Combustion" section be 572/3 = 190.7 kJ/mol? Thanks.—RJH (talk) 21:25, 8 February 2008 (UTC)

No, the heat of combustion is defined per mole of the combustible substance (hydrogen in this case). Since the equation is 2H2 + O2 -> 2H2O, the heat of combustion is −572/2 kJ/mol, or −286 kJ/mol. On the other hand, if you were using the same equation to measure the heat of hydrogenation of oxygen, the value would be −572 kJ/mol since there is only one mole of oxygen. --Itub (talk) 17:13, 12 February 2008 (UTC)

Thank you.—RJH (talk) 19:40, 12 February 2008 (UTC)

"heat of combustion is defined per mole of the combustible substance"

Always? There's some confusion at Talk:Oxyhydrogen#Enthalpy, since the gas being burned is a mixture. — Omegatron 16:56, 30 March 2008 (UTC)

So do I understand this correctly?

2 H₂(g) + O₂(g) → 2 H₂O(l) + 572  kJ (285.83 kJ/mol)

2 H₂(g) + O₂(g) → 2 H₂O(g) + ___  kJ (241.82 kJ/mol)

And the extra heat output is from the state change of water from gas back to liquid? And this is the difference between the two types of Heating value? Which is the more typical measurement for a burning flame? — Omegatron 17:27, 30 March 2008 (UTC)

The difference is the heat of vaporization of water (or rather, the heat of condensation). In chemistry, heats of combustion are normally tabulated in kJ/mol or kcal/mol, which is per mole of the combustible substance. Other fields such as engineering may use other units that they find more practical, such as Mcal/kg or BTU/lb. The way it is traditionally measured, in a bomb calorimeter, the products include liquid water, since the system equilibrates at a temperature close to the original temperature of the bath, around room temperature. However, for the heat initially released by an open flame, I think it might be better to assume water vapor as a product, since the condensation of the water vapor may occur far away from the flame or not at all. --Itub (talk) 09:38, 31 March 2008 (UTC)

So 241.82 kJ/mol would be the "standard" way to refer to it, assuming "/mol" means per mole of hydrogen? — Omegatron 04:22, 4 April 2008 (UTC)

Missing deuterium reference

I was unable to find a suitable source for this statement:

Deuterium comprises 0.0027 – 0.0187% (by mole-fraction or atom-fraction) of hydrogen samples on Earth, with the lower number tending to be found in samples of hydrogen gas and the higher enrichments (0.015% or 150 ppm) typical of ocean water.

If you know of a proper reference, please let us know so we can add it back in. But for now it is unverified, so not suitable for an FA quality article.—RJH (talk) 20:10, 12 February 2008 (UTC)

Chemcial reactions in Production section

I have two suggestions: 1) Could someone add the energies to the chemical equations section? (As is done in the section about Combustion.) 2) There is no need to repeat links to the articles about the reactants so close together. (The earliest reference to carbon monoxide or water or methane should be linked to the appropriate articles; there is no need to repeat a link only a few lines later.) —Preceding unsigned comment added by 206.53.197.12 (talk) 02:04, 14 February 2008 (UTC)

Unsourced additions

The following material has been tagged as missing reference tags but no sources have been provided. As this is an FA article. I am moving the material here until suitable references can be located.

Treating the electron as a matter wave reproduces chemical results such as shape of the hydrogen atom more naturally than the particle-based Bohr model, although the energy and spectral results are the same. Modeling the system fully using the reduced mass of nucleus and electron (as one would do in the two-body problem in celestial mechanics) yields an even better formula for the hydrogen spectra, and also the correct spectral shifts for the isotopes deuterium and tritium. Very small adjustments in energy levels in the hydrogen atom, which correspond to actual spectral effects, may be determined by using a full quantum mechanical theory which corrects for the effects of special relativity (see Dirac equation), and by accounting for quantum effects arising from production of virtual particles in the vacuum and as a result of electric fields (see quantum electrodynamics).

In hydrogen liquid, the electronic ground state energy level is split into hyperfine structure levels because of magnetic effects of the quantum mechanical spin of the electron and proton. The energy of the atom when the proton and electron spins are aligned is higher than when they are not aligned. The transition between these two states can occur through emission of a photon through a magnetic dipole transition. Radio telescopes can detect the radiation produced in this process, which is used to map the distribution of hydrogen in the galaxy.

Thanks.—RJH (talk) 23:27, 29 February 2008 (UTC)

• Ahem. After the important visitors have left the house, can we again pull out all the stuff out that we crammed under the beds and into the closets, so we can go on with living in the house, instead of creeping around in a museum? Wikipedia is supposed to be under construction. There are a lot of "unsourced" statements in it (in fact, there are more unsourced than sourced, for this is how articles grow), and quite often you'll find that this is merely because the needed sources are located in the articles on the linked terms, and haven't been mined out, duplicated, and stuck in. That usually is not grounds to delete an otherwise scientifically sound and non-controversial bit of explanatory writing which improves the encyclopedia.

  Yes, unsourced non-controversial writing DOES improve the encyclopedia. It is better than nothing at all. It simply invites addition of a {{fact}} tag, not deletion. Apparently, somebody has been looking at the language in BLP, which allows controverisal unsourced BLP info to be removed on sight, and has concluded that his also applies to unsourced noncontroversial info, in articles which are about to be reviewed! Say what? Well, I don't see any policy to that effect, and I think the harm to the encyclopedia is obvious.

  Don't delete stuff. Improve it. If you haven't got something better to put in place of something like the above, leave it alone. SBHarris 02:17, 1 April 2008 (UTC)

I agree in general, but in RJH's defense, he based his reason for the move in this being a featured article. Featured articles have stricter referencing standards than the average article, or else they risk becoming "unfeatured". Also, featured articles are supposed to be essentially "complete" (although they can still be improved). --Itub (talk) 06:07, 1 April 2008 (UTC)

Where does it say THAT? I can make as good an argument that a "featured" article is merely one that the community of people who happen to be working on it now, think is about as well as they personally can do with the personnel they have, with the time they have, and for now are sick of, anyway. The idea that it's somehow "complete" even approximately, is totally contrary to the idea of both science and the encyclopedia. It's the sort of reactionary idea I expect to see from writers and scientists who "died" a long time ago, but just haven't been buried yet. SBHarris 17:05, 1 April 2008 (UTC)

I'm just saying that based on what I've seen happen at Featured article review, which is where articles get de-featured. You can check the criteria at WP:FACR. What I called "completeness" (note the scare quotes) is based on the criteria about comprehensiveness and stability. --Itub (talk) 13:16, 2 April 2008 (UTC)

Announcement

We've been working hard trying to find good sources for the information in this article so it can pass FARC. Additions to the article are welcome, but please cite your sources when doing so! Don't make our job any harder.

Stone, you have been making some good changes, but I commented out the section on "mono-atomic" hydrogen. There obviously had to have been a source for this information. Cite it. --Cryptic C62 · Talk 16:52, 9 April 2008 (UTC)

That section was merged in by me from the former Nascent hydrogen article. That article cited no sources. The information was clearly more useful here than there, which is why I merged it. The way, the truth, and the light (talk) 17:05, 9 April 2008 (UTC)

Hydrogen difficult to generate?

From the article, "Although H atoms and H2 molecules are abundant in interstellar space, they are difficult to generate, concentrate, and purify on Earth". It is my understanding that hydrogen can be generated by simply running an electric current through water. This is not difficult. --Xyzzyplugh (talk) 19:34, 14 March 2008 (UTC)

The "difficult" part may mean that the energy cost to extract hydrogen from water is relatively high. Or at least it was; that may be changing.—RJH (talk) 19:57, 14 March 2008 (UTC)

No, it will always require more energy to get hydrogen out of water than you get when burning it or using it in a fuel cell. That's not true of extraction of hydrgen from natural gas (as we do now), but that solves no carbon problems, which is the whole purpose of most of the proposed new hydrogen economy. SBHarris 20:55, 14 March 2008 (UTC)

You misunderstood me once again, but I can't be bothered to argue.—RJH (talk) 21:01, 14 March 2008 (UTC)

The fact that it requires more energy to extract hydrogen from water than you'd get back by using the hydrogen as fuel does not make hydrogen difficult to generate or concentrate or purify. I'm going to remove the sentence, as it's simply not accurate. --Xyzzyplugh (talk) 19:20, 15 March 2008 (UTC)

Accuracy has nothing to do with it, as difficulty is relative and needs qualifiers and references. Is it "accurate" to say that Für Elise is hard to play on the piano, or easy to play? That's sort of the thing we have here. A kg of hydrogen is easier to prepare than a kg of fluorine, but not as easy as a kg of gasoline. SBHarris 07:28, 20 April 2008 (UTC)

(I wonder how well electrolysis can be scaled up?) How about something like "difficult to generate, concentrate, and purify efficiently and economically on Earth" ?

Hydrogen is very easy to obtain. Any interested child with a battery an a couple of wires can make it at home. The main objection here seems to be about its expense and energy balance in the context of use as a fuel. If you are talking about price, give prices. If you are talking about energy, mention energy. But "difficulty" is too vague and subjective. --Itub (talk) 10:07, 23 April 2008 (UTC)

Pauling's Electronegativity

In the article the electronegativity is 2.1, but on Electronegativity and my periodic table...it has it listed as 2.20. Which one is right? Mike6271 (talk) 00:45, 27 March 2008 (UTC)

It is 2.20 according to all the references listed at Electronegativities of the elements (data page), so I'll change it in this article for consistency. --Itub (talk) 10:35, 27 March 2008 (UTC)

Hydrogen donor merger as per header?

This means something in certain kinds of acid-base chemistry, but needs its own article anyway, and surely does not need to disappear and be crammed into this broad article. There's a lot of uses for hydrogen in chemistry, and they can't all be merged here. In fact, hardly any can. This is a broad review article. SBHarris 07:16, 20 April 2008 (UTC)

Oppose merge - it makes the main article too big and at an unsuitable level for the people who would want to read it. Graeme Bartlett (talk) 08:47, 20 April 2008 (UTC)

• I merged Hydrogen donor into Brønsted-Lowry acid-base theory, a much better target and where the synonymous proton donor already redirected. The way, the truth, and the light (talk) 10:02, 20 April 2008 (UTC)

Monoatomic hydrogen

This entire section is dubious and should be deleted. The term "nascent hydrogen" is used only by quacks. The section contains several factual errors on temperature and energy to form atomic hydrogen.

The above user, who has failed to sign, is ignorant. The term 'nascent hydrogen' has a respectable scientific history and is not 'only used by quacks'. In addition his labeling my reverts 'vandalism' in edit summaries is uncivil at least. He should be ignored. The way, the truth, and the light (talk) 17:31, 21 April 2008 (UTC)

A search of Yahoo reveals about a dozen uses of the term "nascent hydrogen" by quacks such as http://www.chechfi.ca/pdfs/hydrogen_injection.pdf . If the term means anything, it means newly made hydrogen such as from electrolysis. Such hydrogen is never "atomic hydrogen". No academic or professional references to nascent hydrogen are available. This term is not used by people who know what they are doing.Trojancowboy (talk) 19:12, 21 April 2008 (UTC)

This is supposed to be a scientific article, not one on cult science. It appears that it is approaching the time for Wikipedia:Dispute_resolution or an editing block on the vandal. Trojancowboy (talk) 19:34, 21 April 2008 (UTC)

User:The way, the truth, and the light was recently blocked for sockpuppetry. In light of this information, I am going to return all disputed content to its original page. Hooray. --Cryptic C62 · Talk 19:58, 12 May 2008 (UTC)

Disputed

Notice of the edit dispute mentioned above has been placed on the WikiProject Elements noticeboard. Since this is a Featured Article, ALL disputed content must be backed up by publications from well-recognized, reputable publishers whose editors fact check or (better yet) peer reviewed journals. Please fix the text to this standard ASAP; text that does not follow Wikipedia's standards of verifiability and relevance will be removed after review by WikiProject Elements members. The disputed tag needs to remain until there is consensus that the article follows Wikipedia content policies. --mav (talk) 02:19, 23 April 2008 (UTC)

Highest atomic weight per nucleon for all elements

I noticed that apparently H-1 (closely followed by the other H-isotopes) has the highest atomic weight per nucleon (1.00785 u) of all currently known isotopes (even more than the heaviest synthetical element, ununoctium, whose isotopes have values of about 1.0007 u per nucleon). Since nuclear reactions only happen naturally if the mass of the resulting particles is smaller than that of the original one(s) (mass=energy by Einstein), this means that hydrogen is in a certain way the "least stable"(!) of the 117 known elements. I don't know if this falls under OR, otherwise it would be a nice "trivia" to add to the article. --129.70.15.202 (talk) 20:33, 13 May 2008 (UTC)