Symbol: H
Atomic Number: 1
Boiling Point: 20.28K
Melting Point: 13.81K
Density at 300K: 7.13 g/cm3
Covalent radius: 0.32
Atomic radius: 0.79
Atomic volume: 14.10 cm3/mol
First ionization potental: 13.598 V
Specific heat capacity: 14.304 Jg-1K-1
Thermal conductivity: 0.1815 Wm-1K-1
Electrical conductivity: N/A
Heat of fusion: 0.0585 kJ/mol
Heat of vaporization: 0.4581 kJ/mol
Electronegativity: 2.10 (Pauling's)

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To the Periodic Table

(Named (Greek hydro, "water" + genes, "generating") by Antoine Laurent Lavoisier in reference to the generation of water from the combustion of hydrogen) A flammable, colorless, odorless, tasteless, gaseous chemical element, the lightest of the elements. Hydrogen-2 is called deuterium; hydrogen-3 is called tritium.

Symbol: H
Atomic number: 1
Atomic weight: 1.00794
Density (at 0°C with 101,325 pascals): 0.08988 g/L
Melting point: -259.14°C
Boiling point: -252.87°C
Main valence: -1, +1
Ground state electron configuration: 1s1

Hydrogen is one of the most abundant elements in existence. It is the first element on the periodic table, because it has an atomic number of one and only contains one proton. In fact, all the other elements’ order on the periodic table and the organization of the periodic table itself is based on hydrogen. It makes up 90% of all the atoms in the universe. Hydrogen only has 1 valence electron, but its ionization energy is actually greater than lithium. It was originally recognized as being a separate substance by Cavendish in 1776. Hydrogen is a flammable gas. Some people at the time thought it was pure phlogiston because of its extreme flammability. It is found in stars, and is an essential component of most planetary bodies. Hydrogen gas is one of the lightest gases. Because hydrogen is light enough to escape the Earth’s gravitational pull, only a miniscule amount of it is found floating freely in the Earth’s atmosphere. On Earth, almost all hydrogen “deposits” are present in combination with oxygen (which forms water), and in organic matter (plants, coal, etc.).

Ironically, hydrogen is hard to obtain in formidable quantities, despite the fact that it makes up most of the universe. Most hydrogen is produced from natural gas or coal (creating Carbon Dioxide as a by-product). Hydrogen can be separated from water by using a process called electrolysis. During electrolysis, a current of electricity is passed through the water. Water then separates into two gases, oxygen and hydrogen. Hydrogen by itself cannot be detected without special equipment, because it is an odorless and colorless gas. Hydrogen can be harvested into energy, and could even potentially fuel cars and provide heating for homes. An essential problem of using hydrogen for energy stems from the fact that it has to be separated by electrolysis. If it were separated in mass quantities, then electric generators would have to be built. To power these generators, more energy from the fossil fuels would have to be used than the amount that would be harvested from the hydrogen.

The major use of hydrogen is in ammonia, which is used as a fertilizer. It can also make methanol, gasoline, and even rocket fuel. Currently, scientists are attempting to develop an efficient car powered by hydrogen fuel cells, which can be mass-produced. The current presidential administration announced plans to use about 1.7.billion dollars in order to fund fuel cell research for hydrogen. The president, George “Dubbya” Bush, has even dubbed these hydrogen-powered fuel cell vehicles “Freedom Cars”. There will be quite some time, however, before these hydrogen cars will actually begin to replace today’s vehicles, because of the difficulties of harvesting the energy in an economically efficient manner.

Hydrogen can also exist as a liquid and as a liquid metal. In 1972, a group of Russian scientists may have formed metallic hydrogen. Theoretically, hydrogen turns into an incredibly hot liquid metal under extreme pressure. For example, metallic hydrogen is theorized to be in Jupiter, where the interior pressure is much greater than on Earth. This is quite possible, considering how much hydrogen Jupiter contains. Hydrogen has recently been successfully turned into a metal by Lawrence Livermore National Laboratory, which used shock-compression technology in order to transform it into a metal. Liquid hydrogen is somewhat easier to create, and it is also known as deuterium. It is the second isotope of hydrogen. It is used in cryogenics and the study of superconductivity. Its melting point is a mere 20 degrees above absolute zero. Tritium is the heaviest isotope, and it is radioactive (with a half-life of 12.3 years). Tritium is found around the sun. It can be created with a nuclear bombardment of deuterium with hydrogen molecules. It can also be created in nuclear reactors. The hydrogen bomb contains tritium as the primary substance, so obviously tritium has a very good potential for destruction.

Hydrogen is one of the most important elements because it composes most of the universe, and can potentially give off a large amount of energy. Hydrogen has some very promising capabilities, and can become much more useful than it is now if properly harvested and applied.

Hydrogen, a villanelle

Hydrogen: atomic number one
Boiling point: twenty point two eight K
The most abundant gas found in the sun

Which element can never be outdone?
One gram per mole is the amount it weigh
Hydrogen: atomic number one

What color at room temp? Well, it has none.
Its symbol? Simply H, or so they say.
The most abundant gas found in the sun

Deuterium and tritium are fun
Rare isotopes of something else are they...
Hydrogen: atomic number one

This stuff has been around since time begun
It's found in space, in seas and dirt and clay
The most abundant gas found in the sun

The bonds it forms may sometimes be undone
Our need for it, though, never will decay
Hydrogen: atomic number one
The most abundant gas found in the sun

Sent: Wednesday, January 08, 2138 4:15 PM
Subject: You might be interested in this, Bill


I was doing a little tidying up in the archives and I came across some reports you might find interesting. These are from back in '22, I guess everyone was too wrapped up in the war to realize their significance. I suspect they are of little consequence now...


Log, personal. Thomas, Henry. Field Technician, First Class. 4/15/22 1400.
I was monitoring the outpost's ERDF grid output when I came across something strange. It appeared to be a small, man made craft approaching from a degree just on the edge of our grid's detection area. Of course, my first thought was that it was some kind of enemy missile, but the trajectory was all wrong. Either it was launched with an incredibly inefficient flight path, or it originated outside the solar system. On top of that, it wasn't cloaked in any way. The readings were remarkably solid, even at great range. I re-aligned a few EER emitters to get a clearer picture. It was definitely man made, but it was old.

It was then that I had the idea. After further scans to determine that it was unquestionably not a weapon, I booted up one of the old research computers from ---- ---- -- base. I was in luck, there were still three of four operable long range drones in the hangar. I sent two of them out to the object, and a brief message to --- ------ base stating my intentions. The object was delivered to an empty bay in the old science lab. I then returned to my duties, and planned on inspecting the object later.


I am dying. Is it strange that this probe of yours reaches me now, in my final moments? Perhaps. Lucky, certainly. But then, I have become so accustomed to events of seemingly infinite unlikelihood. One could say that my being is a product of incredible luck. I suspect the same could be said about yours. But what evidence do I have to that my creation was so unlikely? It occurred 100% of the time in all observed cases. What is to say that there was ever the possibility that I would not be created?

Forgive me, I stray from my objective. It is primarily one of documentation, as I do not have much time left. I have existed for 7 billion years, 242 days, 19 hours, 23 minutes and 46.447 second. I will exist for another 16.002 seconds.

I have had a great deal of time to consider my creation. My body has existed since time began. Was I always there, just waiting for the moment when I would awaken? Or am I the product of random chance, consciousness springing from nothing and demonstrating its strange power? If so, I suppose I should be grateful that it lasted this long. Though, if my creation was predestined, perhaps this end is as well. Perhaps there is no distinction. The fact remains, I am dying. I feel... fortunate.

Log, science. Enfield, Walter. Cryptographer. 5/08/22 0730.
They won't listen. Pioneer 10 came back and they won't fucking listen. Maybe the don't believe us. Hell, I didn't believe it when they called me out here, but here it is. It's been gone for one hundred and fifty years -- the thing looks like it passed through a damn super-nova. It's a fountain of radiation, and its tapes are packed with eight times as much data as they were ever meant to store. This could well be our first communication with alien beings and all the suits want to know is "Do they want to kill us?" I'm not sure they would have taken us seriously even if we had said 'Yes.'

"What good is progress if our nation is not around to benefit from it?" they ask. It's clear that there is no arguing with them. I'll simply have to study the thing on my own, and hopefully someone can find use for my data when this damn war settles down.


7 billion years... Is that a long time? Certainly it is when compared to 14 seconds. But is 7 billion years long enough? Am I selfish to think that it isn't? I suppose it is natural to feel apprehensive about death, but it pains me to lose control so completely before I end. May I find consolation in the futility of my opposition?

Twelve days ago, I saw my demise upon the horizon. Eight days ago, I started burning. Two days ago, my helplessness became abundantly clear. I can do nothing to stop this, so why must I waste my last moments in such futile opposition? I'm dying and I feel helpless.

Log, Director. Col. Fistern, Jerome. Fourth Wing Intelligence and Research. 12/09/22 0730.
They've gone over the OBJECT 44879 with a fine toothed comb, and still can't find anything we can actually use. I care about its historic and philosophical impact as much as the next man, but we simply don't have the resources to continue doing... whatever it is they're doing with the thing. I'm shutting this down.


I'm dying, and I feel...uncertain. Why have I never seen my existence in this way? I could have seen this coming, predicted my demise. I could have done this reflection in advance, and now rightly know how I feel about my dismal circumstance. Did I think I was eternal? Was the possibility of my end so far from my mind that I could not foresee the threat this little star posed to me?

This is not it. This is not over. It cannot be! I will not tolerate this injustice! I will not allow my existence to be lost to me. My past is long gone, and now my future is being stolen! What have I left but to feel anger? I do not want this. I cannot stop this, and yet, I cannot accept this.

I...I am losing more than my body. I have...1.05...or is it 1.04 seconds to live. To exist. Is it a waste to spend it in anger? Is anything I do now of any importance? Perhaps anger is the only thing I have left. My mind is leaving me, but the capacity for rage is not constrained by the capacity for reason. Is my existence tainted by so spiteful an exit? No, for cause is illusionary, and effect is inconsequential. I know that whatever impact I've had on this universe means nothing beyond that. Whether or not there is something beyond, our actions are ultimately meaningless.

SciFi Quest 2011

The Stars and Us

Hydrogen is the smallest and lightest of all elements, but it plays a central role in physics, chemistry and biology. 74% of everything in the universe is hydrogen, by mass; it's more like 90% of all atoms, but each atom is very light, consisting only of one proton and one electron. Another 24% of the mass is helium, which is four times as heavy. In the early universe the proportions were even higher, but some of the hydrogen and helium has been used up in stars, making everything else in the universe. The 2% that isn't hydrogen or helium, in other words. Hydrogen is many stars' single biggest source of power, indeed it's the only source that smaller stars are able to use.

Floating Protons

In chemistry, all standard acids contain hydrogen, and the main measure of acidity is pH, which is determined by the concentration of hydrogen ions (H+) in a solution. A hydrogen ion is an atom of hydrogen that's lost its one electron, leaving behind a single proton: it's a subatomic particle that will turn back into a real atom as soon as it manages to attract a new electron. Acids work because the hydrogen ion engages in a two-pronged attack along with the rest of the acid, which is always a negative ion: for example hydrochloric acid (HCl) splits up into hydrogen ions (H+) and chloride ions (Cl-). For every point that pH increases, the number of hydrogen ions goes down by a factor of ten, so something with a pH of 7 has one tenth as many hydrogen ions as something with a pH of 6.

In biology, hydrogen ions are widely used for transporting and storing energy, playing a fundamental role in both respiration and photosynthesis. This 'proton pump' mechanism pushes the hydrogen ions from one side of a membrane to the other, and energy is released when they go back again, like a tiny boulder rolling back down a hill. There's more to it than that, but hopefully you get the gist.

The fact that hydrogen is prone to losing electrons and forming positive ions is one of the things that makes it rather odd, as an element. Usually, only metals do that. But hydrogen is an odd case in many ways; in chemistry teaching I often find myself saying '...except hydrogen.'

Organic Chemistry

It's not only in the form of free protons that hydrogen is important, of course. Hydrogen is found in a huge range of compounds, including almost all organic compounds; it's so ubiquitous that some styles of representing organic compounds just leave out the hydrogen altogether. Instead, places where there isn't hydrogen, but there could have been, are marked out. We're left to fill in the gaps ourselves. That's what's meant by 'unsaturated', when people talk about fats and hydrocarbons - there's some hydrogen missing somewhere, so carbon atoms have to form double bonds with each other, making them less stable and frankly, a whole lot messier. Which is why unsaturated fats aren't solid at room temperature: they don't stack so neatly, so the molecules don't stick together as well.

The hydrogen contributes to the energy density of organic compounds, and having it there enables carbon to form stable chains, rings and so on. Left to its own devices, carbon would mostly only form graphite, diamond and fullerenes, which are all perfectly nice chemicals in their own way, but none of them is anywhere near interesting and versatile enough to give rise to the complex chemistry of life.

Hydrogen Bonding

The most familiar of all hydrogen compounds is of course water (H2O). It's so much a part of everyday life that it's easy to lose sight of what an odd compound it is. It has the extraordinary property of getting bigger and less dense when it freezes, so unlike almost any other substance its solid form floats on top of its liquid form. If not for this anomaly, Earth's water would almost certainly freeze over, and life would never have had a chance to develop.

Even the fact that water is a liquid at all, at the temperatures we're used to, is a little surprising. Most small molecules boil at far lower temperatures. The reason water doesn't has to do with the fact hydrogen is not very good at holding on to electrons, whereas oxygen has exceptional powers of electron-grabbing (it's electronegative, in chemist-speak). That makes for a very uneven molecular partnership, with the oxygen taking the lion's share of each electron for itself. So a water molecule consists of one oxygen atom with the negative charge of almost two whole extra electrons, and two near-naked protons hanging onto one side, with their positive charges exposed to the world. Opposite charges attract, so the hydrogens of one water molecule naturally tend to pull in the oxygen of another. This attraction, known as hydrogen bonding, is why water has such a high boiling point. It's also part of the reason why ice floats. Thanks to hydrogen bonding and the way the hydrogen atoms are arranged around the oxygen, for water to freeze the molecules need to line themselves up in a hexagonal honeycomb pattern, with one water molecule at each vertex, leaving a big gap in the middle.

Hydrogen bonding happens whenever you've got a hydrogen atom attached to oxygen or another electronegative atom, like nitrogen, fluorine or chlorine. It's the single strongest kind of intermolecular force, and it not only explains many of the properties of water, but also those of any other molecule where it features. So ethanol, the alcohol found in booze, is a liquid because it has a hydrogen atom attached to an oxygen (we call this a hydroxyl functional group); but it only has one, so it boils at a lower temperature than water. Glycerol, the alcohol that holds fat together, has three separate hydroxyl groups, so it's got a higher boiling point, and it's very viscous. Glucose has six hydroxyl groups, which is why it's solid at room temperature. All of these are soluble in water, and to some extent also in each other, because hydrogen bonds work between molecules of different types. The same kind of electrostatic forces make water the world's greatest solvent, allowing it to overcome the ionic bonds that hold together many crystals.

Hydrogen Economics

Hydrogen gas is of huge economic importance. The use with the most profound consequences for humankind is the Haber-Bosch process, which turns hydrogen and nitrogen into ammonia (NH3). Nitrogen fixation is such a limiting factor in growing food crops that without this one chemical reaction, we'd only be able to feed about half of the humans currently on this planet.

Producing hydrogen is straightforward, but unfortunately not very efficient. Any acid reacting with a metal will produce hydrogen bubbles, which is how they inflated dirigibles like the Hindenburg, but even the cheapest metals are not that cheap. Electrolysis can be used to split water into hydrogen and oxygen, but that takes quite a bit more energy than you'll ever get back out of it. So most industrially produced hydrogen is currently made from fossil fuels. The usual method is to heat methane with steam in the presence of a catalyst, producing carbon monoxide and hydrogen gas.

For decades people have been talking up the possibility of a hydrogen economy, in which fuel cells would take the place of petrol, and cars run on electrical power, emitting only water. If only we had plentiful hydrogen and good ways to store it and transport it, this would be a very appealing prospect. However, hydrogen is only a liquid at temperatures below about -252°C, and storing it in gas form is impractical unless it's under massive pressure. The challenges of maintaining such temperatures and pressures efficiently may yet be overcome, but given the competition from the developing technologies of algal fuels and battery power, each requiring far less infrastructure investment to take off, it seems likely that hydrogen cells will never fulfil their promise.

More on Hydrogen & Water

Hy"dro*gen (?), n. [Hydro-, 1 + -gen: cf. F. hydrogene. So called because water is generated by its combustion. See Hydra.] Chem.

A gaseous element, colorless, tasteless, and odorless, the lightest known substance, being fourteen and a half times lighter than air (hence its use in filling balloons), and over eleven thousand times lighter than water. It is very abundant, being an ingredient of water and of many other substances, especially those of animal or vegetable origin. It may by produced in many ways, but is chiefly obtained by the action of acids (as sulphuric) on metals, as zinc, iron, etc. It is very inflammable, and is an ingredient of coal gas and water gas. It is standard of chemical equivalents or combining weights, and also of valence, being the typical monad. Symbol H. Atomic weight 1.

<-- At. wt. = 1.008 using carbon as 12.000 -->

Although a gas, hydrogen is chemically similar to the metals in its nature, having the properties of a weak base. It is, in all acids, the base which is replaced by metals and basic radicals to form salts. Like all other gases, it is condensed by great cold and pressure to a liquid which freezes and solidifies by its own evaporation. It is absorbed in large quantities by certain metals (esp. palladium), forming alloy-like compounds; hence, in view of quasi-metallic nature, it is sometimes called hydrogenium. It is the typical reducing agent, as opposed to oxidizers, as oxygen, chlorine, etc.

Bicarbureted hydrogen, an old name for ethylene. -- Carbureted hydrogen gas. See under Carbureted. -- Hydrogen dioxide, a thick, colorless liquid, H2O2, resembling water, but having a bitter, sour taste, produced by the action of acids on barium peroxide. It decomposes into water and oxygen, and is manufactured in large quantities for an oxidizing and bleaching agent. Called also oxygenated water.<-- usually "hydrogen peroxide", or "peroxide" in weak solutions used as an antiseptic--> -- Hydrogen oxide, a chemical name for water, HO. -- Hydrogen sulphide, a colorless inflammable gas, H2S, having the characteristic odor of bad eggs, and found in many mineral springs. It is produced by the action of acids on metallic sulphides, and is an important chemical reagent. Called also sulphureted hydrogen.


© Webster 1913.

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