Hydrogen»the essentials [WebElements Periodic Table] Element News Hydrogen: the essentials Note that while hydrogen is normally shown at the top of the Group 1 elements in the periodic table, the term "alkaline metal" refers to the Group 1 elements from lithium downwards and not hydrogen. Hydrogen is the lightest element. It is by far the most abundant element in the universe and makes up about about 90% of the universe by weight. It is also the most abundant element in the earth's sun. Hydrogen as water (H2O) is absolutely essential to life and it is present in all organic compounds. Hydrogen is the lightest gas. Hydrogen gas was used in lighter-than-air balloons for transport but is far too dangerous because of the fire risk (Hindenburg). It burns in air to form only water as waste product and if hydrogen could be made on sufficient scale from other than fossil fuels then there might be a possibility of a hydrogen economy. CAS Registry ID : 1333-74-0 Hydrogen: historical information Hydrogen was discovered by Henry Cavendish in 1766 at London, England.

Origin of name : from the Greek words "hydro" and "genes" meaning "water" and "generator". Robert Boyle (1627-1691; English chemist and physicist) published a paper ("New experiments touching the relation betwixt flame and air") in 1671 in which he described the reaction between iron filings and dilute acids which results in the evolution of gaseous hydrogen ("inflammable solution of Mars" [iron]). However it was only much later that it was recognized as an element by Henry Cavendish (1731-1810; an English chemist and physicist who also independently discovered nitrogen) in 1766 when he collected it over mercury and described it as "inflammable air from metals". Cavendish described accurately hydrogen's properties but thought erroneously that the gas originated from the metal rather than from the acid. Hydrogen was named by Lavoisier. Deuterium gas (2H2, often written D2), made up from deuterium, a heavy isotope of hydrogen, was discovered in 1931 by Harold Urey, a professor of chemistry at Chicago and California (both USA).

Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for hydrogen is shown below. [See History of Chemistry, Sir Edward Thorpe, volume 1, Watts & Co, London, 1914.] In 1839 a British scientist Sir William Robert Grove carried out experiments on electrolysis. He used electricity to split water into hydrogen and oxygen.

He then argued one should be able to reverse the electrolysis and so generate electricity from the reaction of oxygen with hydrogen. He enclosed platinum strips in separate sealed bottles, one containing hydrogen and one oxygen. When the containers were immersed in dilute sulphuric acid a current indeed flowed between the two electrodes and water was formed in the gas bottles. He linked several of these devices in series to increase the voltage produced in a gas battery. Later the term fuel cell was used by the chemists Ludwig Mond and Charles Langer. In 1932 Dr Francis Thomas Bacon, an engineer at Cambridge University in the UK, worked further on designs of Mond and Langer. He replaced the platinum electrodes with less expensive nickel gauze and substituted the sulphuric acid electrolyte for alkaline potassium hydroxide (less corrosive to the electrodes). This was in essence the first alkaline fuel cell (AFC) and was called the Bacon Cell. It took Bacon another 27 years to demonstrate a machine capable of producing 5 kW of power, enough to power a welding machine. At about the same time the first fuel cell powered vehicle was demonstrated. Much later fuel cells were by NASA in the 1960s for the Apollo space missions.

Fuel cells have been used for more than 100 missions in NASA spacecraft. Fuel cells are also used in submarines. The lifting agent for the ill fated Hindenberg ballooon was hydrogen rather than the safer helium. The image below is the scene probably in a way you have not seen it before. This is a "ray-traced" image reproduced with the permission of Johannes Ewers , the artist, who won first place with this image in the March/April 1999 Internet Raytracing Competition . For details of ray-tracing you can't beat the POV-Ray site. Hydrogen around us Read more » Hydrogen makes up two of the three atoms in water and water is absolutely essential to life. Hydrogen is present in all organic compounds. A form of water in which both hydrogen atoms are replaced by deuterium (2H, or D) is called "heavy water" (D2O) and is toxic to mammals. Some bacteria are known to metabolise molecular hydrogen (H2). H2 gas is present in the earth's atmosphere in very small quantities, but is present to a far greater extent chemically bound as water (H2O) Water is a constituent of many minerals.

Hydrogen is the lightest element and is by far the most abundant element in the universe, making up about about 90% of the atoms or 75% of the mass, of the universe. Hydrogen is a major constituent of the the sun and most stars. The sun burns by a number of nuclear processes but mainly through the fusion of hydrogen nuclei into helium nuclei. Hydrogen is a major component of the planet Jupiter. In the planet's interior the pressure is probably so great that solid molecular hydrogen is converted into solid metallic hydrogen. Abundances for hydrogen in a number of different environments. More abundance data » Location Second ionisation energy : (no data) kJ mol‑1 Isolation Isolation : in the laboratory, small amounts of hydrogen gas may be made by the reaction of calcium hydride with water. CaH2 + 2H2O → Ca(OH)2 + 2H2 This is quite efficient in the sense that 50% of the hydrogen produced comes from water. Another very convenient laboratory scale experiment follows Boyle's early synthesis, the reaction of iron filings with dilute sulphuric acid.

Fe + H2SO4 → FeSO4 + H2 There are many industrial methods for the production of hydrogen and that used will depend upon local factors such as the quantity required and the raw materials to hand. Two processes in use involve heating coke with steam in the water gas shift reaction or hydrocarbons such as methane with steam. CH4 + H2O (1100°C) → CO + 3H2 C(coke) + H2O (1000°C) → CO + H2 In both these cases, further hydrogen may be made by passing the CO and steam over hot (400°C) iron oxide or cobalt oxide. CO + H2O → CO2 + H2 Read more » The Hydrogen isotope H-2, also known as deuterium, is used in a variety of applications. Deuterium is used extensively in organic chemistry in order to study chemical reactions. It is also used in vitamin research. Deuterium in the form of H2O, known as heavy water, is used as a moderator in CANDU nuclear reactors, in NMR studies and in studies into human metabolism.

Heavy water is also applied in the Sudbury Neutrino Observatory where it is used to study the behavior of neutrinos. Hydrogen - Element information, properties and uses | Periodic Table Chemistry in its element: hydrogen (Promo) You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry. (End promo) Meera Senthilingam This week we hear what its like to be at the top, and number one, as we meet the King of the Elements. Here's Brian Clegg. Brian Clegg Forget 10 Downing Street or 1600 Pennsylvania Avenue, the most prestigious address in the universe is number one in the periodic table, hydrogen. In science, simplicity and beauty are often equated - and that makes hydrogen as beautiful as they come, a single proton and a lone electron making the most compact element in existence. Hydrogen has been around since atoms first formed in the residue of the Big Bang, and is the most abundant element by far. Despite billions of years of countless stars fusing hydrogen into helium it still makes up 75 per cent of the detectable content of the universe.

This light, colourless, highly flammable gas carries on its uniqueness by having the only named isotopes (and some of the best known at that), deuterium with an added neutron in the nucleus and tritium with two neutrons. Hydrogen is an essential for life, the universe and just about everything. Life, in fact, is multiply dependent on it. Without hydrogen we wouldn't have the Sun to give us heat and light. There would be no useful organic compounds to form the building blocks of life. And that most essential substance for life's existence, water, would not exist. It's only thanks to a special trick of hydrogen's that we can use water at all. Hydrogen forms weak bonds between molecules, latching onto adjacent oxygen, nitrogen or fluorine atoms. It's these hydrogen bonds that give water many of its properties. If they didn't exist, the boiling point of water would be below -70 degrees Celsius. Liquid water would not feature on the Earth. Hydrogen was the unwitting discovery of Paracelsus, the sixteenth century Swiss alchemist also known as Theophrastus Philippus Aureolus Bombastus von Hohenheim.

He found that something flammable bubbled off metals that were dropped into strong acids, unaware of the chemical reaction that was forming metal salts and releasing hydrogen, something a number of others including Robert Boyle would independently discover over the years. However, the first person to realize hydrogen was a unique substance, one he called 'inflammable air,' was Henry Cavendish, the noble ancestor of William Cavendish who later gave his name to what would become the world's most famous physics laboratory in Cambridge. Between the 1760s and 1780s, Henry not only isolated hydrogen, but found that when it burned it combined with oxygen (or 'dephlogisticated air' as it was called) to produce water. These clumsy terms were swept aside by French chemist Antoine Lavoisier who changed chemical naming for good, calling inflammable air 'hydrogen', the gene, or creator, of hydro, water. Because hydrogen is so light, the pure element isn't commonly found on the Earth. It would just float away. The prime components of air, nitrogen and oxygen, are fourteen and sixteen times heavier, giving hydrogen dramatic buoyancy.

This lightness of hydrogen made it a natural for one of its first practical uses - filling balloons. No balloon soars as well as a hydrogen balloon. The first such aerial vessel was the creation of French scientist Jacques Charles in 1783, who was inspired by the Montgolfier brothers' hot air success a couple of months before to use hydrogen in a balloon of silk impregnated with rubber. Hydrogen seemed to have a guaranteed future in flying machines, reinforced by the invention of airships built on a rigid frame, called dirigibles in the UK but better known by their German nickname of Zeppelins, after their enthusiastic promoter Graf Ferdinand von Zeppelin. These airships were soon the liners of the sky, carrying passengers safely and smoothly across the Atlantic. But despite the ultimate lightness of hydrogen it has another property that killed off airships - hydrogen is highly flammable. The destruction of the vast zeppelin the Hindenburg, probably by fire caused by static electricity, was seen on film by shocked audiences around the world. The hydrogen airship was doomed. Yet hydrogen has remained a player in the field of transport because of the raw efficiency of its combustion.

Many of NASA's rockets, including the second and third stages of the Apollo Program's Saturn V and the Space Shuttle main engines, are powered by burning liquid hydrogen with pure oxygen. More recently still, hydrogen has been proposed as a replacement for fossil fuels in cars. Here it has the big advantage over petrol of burning to provide only water. No greenhouse gasses are emitted. The most likely way to employ hydrogen is not to burn it explosively, but to use it in a fuel cell, where an electrochemical reaction is used to produce electricity to power the vehicle. Not everyone is convinced that hydrogen fuelled cars are the future, though. We would need a network of hydrogen fuel stations, and it remains a dangerous, explosive substance. At the same time, it is less efficient than petrol, because a litre of petrol has about three times more useful energy in it than a litre of liquid hydrogen (if you use compressed hydrogen gas that can go up to ten times more). The other problem is obtaining the hydrogen. It either comes from hydrocarbons, potentially leaving a residue of greenhouse gasses, or from electrolysing water, using electricity that may not be cleanly generated.

But even if we don't get hydrogen fuelled cars, hydrogen still has a future in a more dramatic energy source - nuclear fusion, the power source of the sun. Fusion power stations are tens of years away from being practical, but hold out the hope of clean, plentiful energy. However we use hydrogen, though, we can't take away its prime position. It is numero uno, the ultimate, the king of the elements. Meera Senthilingam So it's the most abundant element, is essential for life on earth, fuels space rockets and could resolve our fossil fuel dependents. You can see why Brian Clegg classes hydrogen as number one. Now next week we meet the time keeper of the periodic table. Tom Bond One current use is in atomic clocks, though rubidium is considered less accurate than caesium. The rubidium version of the atomic clock employs the transition between two hyperfine energy states of the rubidium-87 isotope. These clocks use microwave radiation which is tuned until it matches the hyperfine transition, at which point the interval between wave crests of the radiation can be used to calibrate time itself.

Meera Senthilingam And to find out more of the roles of Rubidium join Tom Bond on next week's Chemistry in its Element. Until then I'm Meera Senthilingam, thanks for listening and goodbye. (Promo) Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com . There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements . (End promo) It's Elemental - The Element Hydrogen It's Elemental Melting Point: 13.81 K (-259.34°C or -434.81°F) Boiling Point: 20.28 K (-252.87°C or -423.17°F) Density: 0.00008988 grams per cubic centimeter Phase at Room Temperature: Gas Element Classification: Non-metal Period Number: 1 Group Number: 1 Group Name: none What's in a name? From the Greek words hydro and genes, which together mean "water forming." Say what? Hydrogen is pronounced as HI-dreh-jen.

History and Uses: Scientists had been producing hydrogen for years before it was recognized as an element. Written records indicate that Robert Boyle produced hydrogen gas as early as 1671 while experimenting with iron and acids. Hydrogen was first recognized as a distinct element by Henry Cavendish in 1766. Composed of a single proton and a single electron , hydrogen is the simplest and most abundant element in the universe . It is estimated that 90% of the visible universe is composed of hydrogen. Hydrogen is the raw fuel that most stars 'burn' to produce energy. The same process, known as fusion, is being studied as a possible power source for use on earth. The sun's supply of hydrogen is expected to last another 5 billion years. Hydrogen is a commercially important element. Large amounts of hydrogen are combined with nitrogen from the air to produce ammonia (NH3) through a process called the Haber process. Hydrogen is also added to fats and oils, such as peanut oil, through a process called hydrogenation. Liquid hydrogen is used in the study of superconductors and, when combined with liquid oxygen , makes an excellent rocket fuel. Hydrogen combines with other elements to form numerous compounds.

Some of the common ones are: water (H2O), ammonia (NH3), methane (CH4), table sugar (C12H22O11), hydrogen peroxide (H2O2) and hydrochloric acid (HCl). Hydrogen has three common isotopes . The simplest isotope, called protium, is just ordinary hydrogen. The second, a stable isotope called deuterium , was discovered in 1932. The third isotope, tritium , was discovered in 1934. Estimated Crustal Abundance: 1.40×103 milligrams per kilogram Estimated Oceanic Abundance: 1.08×105 milligrams per liter Number of Stable Isotopes: 2 ( View all isotope data ) Ionization Energy: 13.598 eV Periodic Table of the Elements Periodic Table of the Elements By Tim Sharp, Reference Editor | January 5, 2016 11:24am ET MORE The classic Periodic Table organizes the chemical elements according to the number of protons that each has in its atomic nucleus.

Credit: Karl Tate, Livescience.com contributor The Periodic Table of the Elements arranges all of the known elements in an informative array. Elements are arranged in order of increasing atomic number. Order generally coincides with increasing atomic mass. The different rows of elements are called periods. The period number of an element signifies the highest energy level an electron in that element occupies (in the unexcited state), according to the Los Alamos National Laboratory . The number of electrons in a period increases as one moves down the periodic table; therefore, as the energy level of the atom increases, the number of energy sub-levels per energy level increases. Elements that lie in the same column on the periodic table (called a "group") have identical valance electron configurations and consequently behave in a similar fashion chemically. For instance, all the group 18 elements are inert gases. [ Related: How Are the Elements Grouped? ] The periodic table contains an enormous amount of important information: Atomic Number: The number of protons in an atom defines what element it is. For example, carbon atoms have six protons, hydrogen atoms have one, and oxygen atoms have eight. The number of protons in an atom is referred to as the atomic number of that element.

The number of protons in an atom also determines the chemical behavior of the element. Element Symbol: The element symbol is one, two or three letters chosen to represent an element ("H" for hydrogen, "Kr" for krypton, "Uup" for Ununpentium, etc.). These symbols are used internationally. Atomic Weight: The standard atomic weight is the average mass of an element in atomic mass units ("amu"). Though individual atoms always have an integer number of atomic mass units, the atomic mass on the periodic table is stated as a decimal number because it is an average of the various isotopes of an element. The average number of neutrons for an element can be found by subtracting the number of protons (atomic number) from the atomic mass. Atomic weight for elements 93-118: For naturally occurring elements, the atomic weight is calculated from averaging the weights of the natural abundances of the isotopes of that element. However, for man-made trans-uranium elements there is no "natural" abundance. The convention is to list the atomic weight of the longest-lived isotope in the periodic table. These atomic weights should be considered provisional since a new isotope with a longer half-life could be produced in the future.

Within this man-made category are the superheavy elements, or those with atomic numbers above 104. The larger the atom's nucleus — which increases with the number of protons inside — the more unstable that element is, generally. As such, these outsized elements are fleeting, lasting mere milliseconds before decaying into lighter elements, according to the International Union of Pure and Applied Chemistry (IUPAC). For instance, superheavy elements 113, 115, 117 and 118 were just verified by the IPUAC in December 2015, completing the seventh row, or period, on the table. Several different labs produced the superheavy elements. "The chemistry community is eager to see its most cherished table finally being completed down to the seventh row. IUPAC has now initiated the process of formalizing names and symbols for these elements," Jan Reedijk, president of the Inorganic Chemistry Division of IUPAC, said in an IUPAC statement . Element articles WebElements Periodic Table of the Elements No [259.10] The standard form of the periodic table includes periods (shown horizontally) and groups (shown vertically). Elements in groups have some similar properties to each other.

There is no one single or best structure for the periodic table but by whatever consensus there is, the form used here in WebElements is very useful. The periodic table is a masterpiece of organised chemical information. The evolution of chemistry's periodic table into the current form is an astonishing achievement with major contributions from many now famous chemists and other eminent scientists. Buy periodic table posters and periodic table fridge magnets You can buy these periodic table posters online and others at our WebElements periodic table shop . Element 117 discovered On 1 May 2014 a paper published in Phys. Rev. Lett by J. Khuyagbaatar and others states the superheavy element with atomic number Z = 117 (ununseptium) was produced as an evaporation residue in the 48Ca and 249Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allows measurement of decays of single atomic nuclei with very short half-lives .

Two decay chains comprising seven α-decays and a spontaneous fission each were identified and assigned to the isotope 294Uus (element 117) and its decay products. WebElements: Periodic Table of the Elements - AstroEd AstroEd Periodic Table of the Elements From AstroEd Elements The chemical elements are the basic atoms, from which all chemical compounds are made. All chemical elements are listed in the Periodic Table of Elements . Each has an atomic number, the number of protons in that atom. Hydrogen (H) has one proton in its nucleus, Helium (He) has 2, and so on. The atomic mass is roughly the number of protons + neutrons (plus a little more for the electrons and the fact that a neutron is slightly more massive than a proton). Most light atoms have the same number of neutrons as protons. So the atomic mass of He is (2 protons + 2 neutrons) roughly 4 (plus a little more).

The exceptions are (1) Hydrogen, which is found most often as a proton with an electron and no neutron, and (2) the heaviest elements, which need more neutrons to glue the atom together keeping the protons from repelling each other. For example, copper has an atomic number of 29 (29 protons) but an atomic mass, not of 58 but of 63 meaning it has 34 neutrons. (Specifically one atomic mass unit equals 1/12th the mass of a carbon atom, but it is easiest just to look up the atomic mass on the Periodic Table.) Atoms are normally neutral, that is there are the same number of protons (positive charges) in an atom, as there are electrons (negative charges). If an atom has too many or too few electrons, it is called an ion. If there are too many electrons it is a negative ion (since electrons have a negative charge.) If it has too few electrons it is a positive ion. Dissolve table salt in water and the NaCl molecule becomes Na+and Cl- in solution.

In the Earth's atmosphere, N2 (nitrogen molecule) and O2 (oxygen molecule) may lose an electron when struck by a cosmic ray and become the ions N2+ and O2+. Sunlight and starlight can ionize elements and compounds. In interstellar gas, neutral H atoms may become H+, a bare proton with no electron. If positive ions and negative ions are adjacent, and the environment is right, they will naturally combine . Another way elements can combine to form compounds is by covalent bonding , sharing electrons. Chemical elements combine to make chemical compounds, such as water (H2O) or olivine ( ( Mg Fe )2 Si O 4) and organic compounds such as amino acids which make up proteins, and nucleotide bases (purines and pyrimidines) which make up DNA and RNA ... the building blocks of Life. An atom of helium, a chemical element Periodic Table of Chemical Elements Elements formed during the Big Bang, by fusion in stars, and by shockwaves in supernovae Origins of Elements The Big Bang At the time of the Big Bang, pressure and temperatures were such that subatomic particles could form. As conditions changed so did the types of particles that formed.

Electrons, quarks, protons and neutrons, all happened in a fraction of a second. Helium ions, 2 protons and 2 neutrons in one nucleus, were present after 3 minutes. Not until 300,000 years later was the universe cool enough to allow protons, helium and other nuclei to capture electrons to create atoms of hydrogen, and helium, and traces of lithium and beryllium. To this day the most abundant element in the universe is still hydrogen. It shows up as a magenta color in many star forming nebulae, such as the Horsehead Nebula where hydrogen is reacting with starlight. The dark absorbing cloud that forms the familiar shape and blocks our view of stars behind the nebula, is dust, mostly made of carbon. Exaggerated magenta-colored ionized hydrogen in the Horsehead Nebula T.A.Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA) Fusion in Stars As gravity pulled the hydrogen and helium together the earliest stars formed.

Fusion inside stars would convert hydrogen (H) to more helium (He), then to carbon (C), and depending on the size of the star, the process might continue up to iron (Fe), but nothing heavier could fuse in a star and still release energy. Stars in M 103 fusing elements When small stars die they spew out these new heavier elements. These are caught up in later star-forming nebulae, so that solid planets may form around second and third generation stars. The carbon in the Horsehead Nebula came from inside stars. Planetary nebulae from dying stars throwing off their outer layers Shock Waves in Supernovae When giant stars die, they not only send out elements up to iron, but in the shockwaves from their explosive supernova, create elements heavier than iron, such as silver (Ag), gold (Au), and platinum (Pt). Supernova remnants: Crab Nebula and remnants from a pair of Supernovae DEM L316 Credit: Gemini Observatory In the dense early Universe the first stars would have been huge. The larger the stars, the more gravitational pressure, and the faster they use up their fuel.

These giant stars lasted only a few million years, then exploded in violent supernovae. Supernova remnants would fly out into space, to be caught up by later generations of stars. Copper (Cu), zinc (Zn), and iodine (I), were among the elements made in supernovae, elements which in trace amounts are necessary for Life. Vela supernova remnants Every living thing is made of bits of Big Bang (H), chemicals fused in stars (O) (C), and bits of Supernova remnants (Cu) ! Every living thing has stardust in it. Origins of Chemical Compounds But where did water ( H2O ), olivine ( ( Mg, Fe )2SiO4 ), and amino acids (such as C3H5NO ) come from? When dying stars explode and make beautiful planetary nebulae and supernova remnants, they spew out heavy elements that had been fused in their cores.

Dumbbell Nebula (M27), a "planetary" nebula from a dying star Detail of the Dumbbell Nebula showing knots of heavy elements flying out from the dying star In the intense heat inside a star, chemical compounds cannot form, but as dense clouds of gas and dust are kicked out into space they cool. When conditions and temperature are right, elements bond and create compounds. The denser the environment, the more likely elements are to collide and form compounds. This may happen either in gaseous knots, or in Bok globules in giant star-forming nebulae where dust may be seen gathering under the influence of its own gravity (below), or in protoplanetary disks where dust is collecting to form stars and their planets. We can tell what compounds are present in the molecular clouds of star forming nebulae, because patterns show up in their spectra just they do for the atomic elements. Nebula in Large Magellanic Cloud where stars are forming Bok Globules before they become protoplanetary disks Protoplanetary disks, where future planets are forming around future stars, in the Orion Nebula Water Water (H2O) Everyone's favorite compound is water.

H2O forms naturally in space, through chemical reactions on the surface of dust grains and in cold dense gas. Water on the cold dust remains ice as long as it is cold, eventually finding its way into the disk from which planets form. NASA has an airborn observatory to study how this happens. The processes that determine water formation and destruction depend on temperature. You know that hydrogen "burns", and in the presence of oxygen it will self ignite at 550 C (1022 F) and form water. In the protoplanetary disk, from which the solar system formed, water was present in large quantities. It was ice in the cold outer regions, and gas was where it was warmer, closer to the early Sun. Above 3000 C water will dissociate into OH and H, so there is no water in the atmosphere of the Sun or close to it. However, even when it is cold, unprotected by a planetary atmosphere or by dust in the disk, water is dissociated by sunlight. Its oxygen and hydrogen atoms are ionized, and blown out by the solar wind.

Small bodies like Mercury or the Moon had too little gravity to hold on to water, and no atmosphere to prevent its dissociation and loss. In the outer solar system, water and ice were retained by some of the satellites of Jupiter and Saturn. The Oort Cloud, a remant of the solar nebula, is where icy comets still reside. In thick protective atmospheres, water could have been held by early planets until they were cool enough to have rain. This, and comets, would continue to bring water to the busy early solar system, enough water to fill the oceans. The Earth still has its water and is warm enough for liquid oceans. Colder Mars also has its water, hidden as ice under the soil. Olivine and Pallasite Meteorites A pallasite meteorite Olivine ((Mg,Fe)2SiO4) would also form in the protoplanetary nebula. If a planet or asteroid is large enough, it forms layers differentiating different minerals, with heaviest elements, usually iron, in the center. In a powerful enough collision, the iron, with a lower melting point than olivine, melts around the fragments of olivine. Together they fly out making beautiful pallasites.

It is possible to get an idea of the energy in an impact of this sort by the heat that is generated, which would be above the melting point of iron, 1535 C, but not so hot as to melt olivine, 1760 C. Molten iron envelops pieces of olivine (which in its pure form is the gemstone peridot) in a pallasite meteorite Organic Compunds such as Amino Acids and Nucleotide Bases The Murchison Meteorite Carbonaceous chondrites are a type of meteorite known to contain high concentrations of water and organic compounds. The Murchison Meteorite , which fell near Murchison, Australia, in 1969, has been found to contain over 100 amino acids , some rarely seen on Earth, and also purines and pyrimidines , nucleotide bases that are building blocks of DNA and RNA. This discovery shows that amino acids and components of the genetic code, were already present in the early solar system, available not only to Earth but to other planets and moons as well.

In addition to organic chemicals coming via meteorites, seventeen of the twenty amino acids have been produced in the laboratory, in experiments simulating the early Earth , complete with water, heat, and an electric spark for lightning. Amino acids are made up simply of hydrogen (H), carbon (C), oxygen (O), and nitrogen (N), and occasionally sulfur (S). Amino acids are alike and different While amino acids are the building blocks of proteins, purines and pyrimidines (also called nucleobases or nucleotide bases) are the building blocks of DNA and RNA. They, also, are simple compounds of hydrogen (H), carbon (C), oxygen (O), and nitrogen (N), all found in the interstellar gas from which stars and planets form. Purines and pyrimidines are building blocks of DNA and RNA These nucleotide bases are abbreviated A,G,C, T, and U. A, G, C, T make DNA A, G, C, U make RNA When strung together they make the genetic code: all of which formed in the early solar nebula, and all of which could have landed on any planet or moon.

Since these happened around our star, it is likely that organic molecules formed around other stars as well, making life a definite possibility elsewhere in the Universe. 10 Hydrogen Facts 10 Hydrogen Facts 10 Hydrogen Facts Quick Facts about the Element Hydrogen Over 75% of the matter in the universe is hydrogen. Helium accounts for most of the other quarter, with the other elements accounting for less than one percent. Reinhold Wittich/Stocktrek Images, Getty Images By Anne Marie Helmenstine, Ph.D. Updated February 01, 2016. Hydrogen is the chemical element with the element symbol H and atomic number 1. It's essential for all life and abundant in the universe, so it's one element you should get to know better. Here are basic facts about the first element in the periodic table, hydrogen. Atomic Number : 1 Hydrogen is the first element in the periodic table , meaning it has an atomic number of 1 or 1 proton in each hydrogen atom. The name of the element comes from the Greek words hydro for "water" and genes for "forming," since hydrogen bonds with oxygen to form water (H2O).

Robert Boyle produced hydrogen gas in 1671 during an experiment with iron and acid, but hydrogen wasn't recognized as an element until 1766 by Henry Cavendish. Atomic Weight : 1.00794 This makes hydrogen the lightest element. It is so light, the pure element isn't bound by Earth's gravity. So, there is very little hydrogen gas left in the atmosphere. Massive planets, such as Jupiter, consist mainly of hydrogen, much like the Sun and stars. Even though hydrogen, as a pure element, bonds to itself to form H2, it's still lighter than a single atom of helium because most hydrogen atoms don't have any neutrons. In fact, two hydrogen atoms (1.008 atomic mass units per atom) are less than half the mass of one helium atom (atomic mass 4.003). continue reading below our video What are the Seven Wonders of the World Hydrogen is the most abundant element . About 90% of the atoms and 75% of the element mass of the universe is hydrogen.

Although hydrogen is the most abundant element in the human body in terms of numbers of atoms of the element, it's only 3rd in abundance by mass, after oxygen and carbon, because hydrogen is so light. There are three natural isotopes of hydrogen: protium , deuterium , and tritium . The most common isotope of hydrogen is protium, which has 1 proton, 0 neutrons , and 1 electron. This makes hydrogen the only element that can have atoms without any neutrons! Deuterium has 1 proton, 1 neutron, and 1 electron. Although this isotope is heavier than protium, deuterium is not radioactive. However, tritium does emit radiation. Tritium is the isotope with 1 proton, 2 neutrons, and 1 electron. Hydrogen gas is extremely flammable. It is used as a fuel by the space shuttle main engine and was associated with the famous explosion of the Hindenburg airship. While many people consider oxygen to be flammable, it actually doesn't burn . However, it's an oxidizer, which is why hydrogen is so explosive in air or with oxygen. Hydrogen compounds commonly are called hydrides.

Hydrogen may be produced by reacting metals with acids (e.g., zinc with hydrochloric acid). The physical form of hydrogen at room temperature and pressure is a colorless and odorless gas. The gas and liquid are nonmetals, but when hydrogen is compressed into a solid, the element is an alkali metal . Solid crystalline metallic hydrogen has the lowest density of any crystalline solid. Hydrogen has many uses, though most hydrogen is used for processing fossil fuels and in the production of ammonia. It is gaining importance as an alternate fuel that produces energy by combustion, similar to what happens in fossil fuel engines. Hydrogen is also used in fuel cells that react hydrogen and oxygen to produce water and electricity. In compounds, hydrogen can take a negative charge (H-) or a positive charge (H+). Bonus Fact: Hydrogen is the only atom for which the Schrödinger equation has an exact solution. Periodic Table of Elements: Los Alamos National Laboratory 1, -1 History From the Greek word hydro (water), and genes (forming). Hydrogen was recognized as a distinct substance by Henry Cavendish in 1776. Diagram of a simple hydrogen atom.

Hydrogen is the most abundant of all elements in the universe. The heavier elements were originally made from hydrogen atoms or from other elements that were originally made from hydrogen atoms. Sources Hydrogen is estimated to make up more than 90% of all the atoms -- three quarters of the mass of the universe! This element is found in the stars, and plays an important part in powering the universe through both the proton-proton reaction and carbon-nitrogen cycle. Stellar hydrogen fusion processes release massive amounts of energy by combining hydrogens to form helium . Production of hydrogen in the U.S. alone amounts to about 3 billion cubic feet per year. Hydrogen is prepared by steam on heated carbon , decomposition of certain hydrocarbons with heat, reaction of sodium or potassium hydroxide on aluminum electrolysis of water, or displacement from acids by certain metals. Liquid hydrogen is important in cryogenics and in the study of superconductivity, as its melting point is only 20 degrees above absolute zero. Tritium is readily produced in nuclear reactors and is used in the production of the hydrogen bomb. Hydrogen is the primary component of Jupiter and the other gas giant planets.

At some depth in the planet's interior the pressure is so great that solid molecular hydrogen is converted to solid metallic hydrogen. In 1973, a group of Russian experimenters may have produced metallic hydrogen at a pressure of 2.8 Mbar. At the transition the density changed from 1.08 to 1.3 g/cm3. Earlier, in 1972, at Livermore, California, a group also reported on a similar experiment in which they observed a pressure-volume point centered at 2 Mbar. Predictions say that metallic hydrogen may be metastable; others have predicted it would be a superconductor at room temperature. Compounds Although pure hydrogen is a gas, we find very little of it in our atmosphere. Hydrogen gas is so light that, uncombined, hydrogen will gain enough velocity from collisions with other gases that they will quickly be ejected from the atmosphere. On earth, hydrogen occurs chiefly in combination with oxygen in water, but it is also present in organic matter such as living plants, petroleum, coal, etc. It is present as the free element in the atmosphere, but only less than 1 ppm by volume.

The lightest of all gases, hydrogen combines with other elements -- sometimes explosively -- to form compounds. Uses Great quantities of hydrogen are required commercially for nitrogen fixation using the Haber ammonia process, and for the hydrogenation of fats and oils. It is also used in large quantities in methanol production, in hydrodealkylation, hydrocracking, and hydrodesulfurization. Other uses include rocket fuel, welding, producing hydrochloric acid, reducing metallic ores, and filling balloons. The lifting power of 1 cubic foot of hydrogen gas is about 0.07 lb at °C, 760 mm pressure. The hydrogen fuel cell is a developing technology that will allow great amounts of electrical power to be obtained using a source of hydrogen gas. Consideration is being given to an entire economy based on solar- and nuclear-generated hydrogen. Public acceptance, high capital investment, and the high cost of hydrogen with respect to today's fuels are but a few of the problems facing such an economy. Located in remote regions, power plants would electrolyze seawater; the hydrogen produced would travel to distant cities by pipelines.

Pollution-free hydrogen could replace natural gas, gasoline, etc., and could serve as a reducing agent in metallurgy, chemical processing, refining, etc. It could also be used to convert trash into methane and ethylene. Forms Quite apart from isotopes, it has been shown that under ordinary conditions hydrogen gas is a mixture of two kinds of molecules, known as ortho- and para-hydrogen, which differ from one another by the spins of their electrons and nuclei. Normal hydrogen at room temperature contains 25% of the para form and 75% of the ortho form. The ortho form cannot be prepared in the pure state. Since the two forms differ in energy, the physical properties also differ. The melting and boiling points of parahydrogen are about 0.1°C lower than those of normal hydrogen. Isotopes The ordinary isotope of hydrogen, H, is known as Protium, the other two isotopes are Deuterium (a proton and a neutron) and Tritium (a protron and two neutrons). Hydrogen is the only element whose isotopes have been given different names. Deuterium and Tritium are both used as fuel in nuclear fusion reactors.

One atom of Deuterium is found in about 6000 ordinary hydrogen atoms. Deuterium is used as a moderator to slow down neutrons. Tritium atoms are also present but in much smaller proportions. Tritium is readily produced in nuclear reactors and is used in the production of the hydrogen (fusion) bomb. It is also used as a radioactive agent in making luminous paints, and as a tracer. List of Elements of the Periodic Table - Sorted by Atomic number energy (eV) Notes: • Density of elements with boiling points below 0°C is given in g/l and in sorted list they are shown before other elements with boling point >0°C. • Earth crust composition average values are from a report by F. W. Clarke and H. S. Washington, 1924. Elemental composition of crustal rocks differ between different localities ( see article ). • Group: There are only 18 groups in the periodic table that constitute the columns of the table. Lanthanoids and Actinoids are numbered as 101 and 102 to separate them in sorting by group. Abbreviations and Definitions: M.P. - melting point B.P.

- boiling point Atomic number: The number of protons in an atom. Each element is uniquely defined by its atomic number. Atomic mass: The mass of an atom is primarily determined by the number of protons and neutrons in its nucleus. Atomic mass is measured in Atomic Mass Units (amu) which are scaled relative to carbon, 12C, that is taken as a standard element with an atomic mass of 12. This isotope of carbon has 6 protons and 6 neutrons. Thus, each proton and neutron has a mass of about 1 amu. Isotope: Atoms of the same element with the same atomic number, but different number of neutrons. Isotope of an element is defined by the sum of the number of protons and neutrons in its nucleus. Elements have more than one isotope with varying numbers of neutrons. For example, there are two common isotopes of carbon, 12C and 13C which have 6 and 7 neutrons respectively. The abundances of different isotopes of elements vary in nature depending on the source of materials. For relative abundances of isotopes in nature see reference on Atomic Weights and Isotopic Compositions .

Atomic weight: Atomic weight values represent weighted average of the masses of all naturally occurring isotopes of an element. The values shown here are based on the IUPAC Commission determinations ( Pure Appl. Chem. 73:667-683, 2001 ). The elements marked with an asterisk have no stable nuclides. For these elements the weight value shown represents the mass number of the longest-lived isotope of the element. Electron configuration: The distribution of electrons according to the energy sublevels (subshells) in uncharged atoms. The noble gas shown in square brackets (e.g. [He]), marks that all the subshells associated with that element are fully occupied by electrons. Energy levels and sublevels

Question: The element hydrogen has which number on the Periodic Table?
Answer: 1