Why Is Hydrogen in a Family by Itself
Chemistry of Hydrogen (Z=ane)
- Folio ID
- 590
Hydrogen is a colorless, odorless and tasteless gas that is the nigh abundant chemical element in the known universe. It is also the lightest (in terms of atomic mass) and the simplest, having only one proton and one electron (and no neutrons in its about common isotope). It is all around us. Information technology is a component of water (H2O), fats, petroleum, table carbohydrate (C6H12Osix), ammonia (NH3), and hydrogen peroxide (H2O2)—things essential to life, as we know it.
Hydrogen Facts
- Atomic Number: i
- Atomic Symbol: H
- Atomic Weight: 1.0079
- Electronic Configuration: 1s1
- Oxidation States: one, -1
- Atomic Radius: 78 pm
- Melting Signal: -259.34°C
- Boiling Betoken: -252.87° C
- Elemental Classification: Not-Metal
- At Room Temperature: Colorless & Odorless Diatomic Gas
History of Hydrogen
Hydrogen comes from Greek meaning "water producer" ("hydro" =water and "gennao"=to brand). First isolated and identified equally an element by Cavendish in 1766, hydrogen was believed to be many unlike things. Cavendish himself idea that it was "inflammable air from metals", owing to its product past the action of acids on metals. Before that, Robert Boyle and Paracelsus both used reactions of iron and acids to produce hydrogen gas and Antoine Lavoisier gave hydrogen its proper noun because it produced water when ignited in air. Others idea it was pure phlogiston because of its flammability. Hydrogen is among the ten most abundant elements on the planet, but very little is plant in elemental form due to its low density and reactivity. Much of the terrestrial hydrogen is locked up in h2o molecules and organic compounds like hydrocarbons.
Properties of Hydrogen
Hydrogen is a nonmetal and is placed above grouping in the periodic table because it has nsi electron configuration like the brine metals. Still, information technology varies greatly from the alkali metals as it forms cations (H+) more reluctantly than the other brine metals. Hydrogen's ionization energy is 1312 kJ/mol, while lithium (the brine metal with the highest ionization energy) has an ionization energy of 520 kJ/mol.
Because hydrogen is a nonmetal and forms H- (hydride anions), it is sometimes placed above the halogens in the periodic table. Hydrogen likewise forms H2 dihydrogen similar halogens. However, hydrogen is very different from the halogens. Hydrogen has a much smaller electron analogousness than the halogens.
Hii dihydrogen or molecular hydrogen is non-polar with two electrons. There are weak attractive forces between Htwo molecules, resulting in depression boiling and melting points. However, Htwo has very potent intramolecular forces; Htwo reactions are generally slow at room temperature due to stiff H—H bail. H2 is easily activated by estrus, irradiation, or catalysis. Activated hydrogen gas reacts very quickly and exothermically with many substances.
Hydrogen also has an ability to grade covalent bonds with a large variety of substances. Because it makes strong O—H bonds, information technology is a good reducing agent for metal oxides. Instance: CuO(s) + H2(thou) → Cu(s) + H2O(g) Hii(yard) passes over CuO(s) to reduce the Cu2+ to Cu(due south), while getting oxidized itself.
Reactions of Hydrogen
Hydrogen's low ionization energy makes it act similar an brine metallic:
\[H_{(grand)} \rightarrow H^+_{(g)} + e^-\]
However, information technology half-filled valence vanquish (with a \(1s^1\) configuration) with one \(e^-\) too causes hydrogen to act like a halogen non-metallic to gain noble gas configuration past calculation an additional electron
\[H_{(m)} + e^- \rightarrow H^-_{(g)}\]
Reactions of Hydrogen with Active Metals
Hydrogen accepts e- from an active metal to form ionic hydrides like LiH. By forming an ion with -1 charge, the hydrogen behaves like a halogen.
Group ane metals
\[2M_{(south)}+H_{two(1000)} \rightarrow 2MH_{(s)}\]
with \(M\) representing Group 1 Brine metals
Examples:
- \(2K_{(s)}+H_{2(g)} \rightarrow 2KH_{(south)}\)
- \(2K_{(s)}+Cl_{2(m)} \rightarrow 2KCl_{(s)}\)
Group two metals
\[M_{(s)}+H_{two(grand)} \rightarrow MH_{ii(s)}\]
with \(M\) representing Grouping 2 Alkaline Globe metals
Example:
- \(Ca_{(s)}+H_{two(g)} \rightarrow CaH_{2(southward)}\)
- \(Ca_{(s)}+Cl_{2(m)} \rightarrow CaCl_{2(s)}\)
Reactions of Hydrogen with Nonmetals
Unlike metals forming ionic bonds with nonmetals, hydrogen forms polar covalent bonds. Despite being electropositive like the active metals that course ionic bonds with nonmetals, hydrogen is much less electropositive than the agile metals, and forms covalent bonds.
Hydrogen + Halogen → Hydrogen Halide
\[H_{2(g)}+ Cl_{2(thousand)} \rightarrow HCl_{(g)}\]
Hydrogen gas reacting with oxygen to produce water and a large amount of heat: Hydrogen + Oxygen → Water
\[(H_{2(g)}+O_{ii(grand)} \rightarrow H_2O_{(g)}\]
Reactions with Transition Metals
Reactions of hydrogen with Transition metals (Group three-12) form metallic hydrides. There is no fixed ratio of hydrogen atom to metallic because the hydrogen atoms fill holes between metal atoms in the crystalline construction.
Uses & Application
The vast majority of hydrogen produced industrially today is made either from treatment of methane gas with steam or in the product of "water gas" from the reaction of coal with steam. Most of this hydrogen is used in the Haber procedure to manufacture ammonia.
Hydrogen is also used for hydrogenation vegetable oils, turning them into margarine and shortening, and some is used for liquid rocket fuel. Liquid hydrogen (combined with liquid oxygen) is a major component of rocket fuel (as mentioned higher up combination of hydrogen and oxygen relapses a huge amount of free energy). Because hydrogen is a adept reducing agent, it is used to produce metals like iron, copper, nickel, and cobalt from their ores.
Because one cubic feet of hydrogen can lift about 0.07 lbs, hydrogen lifted airships or Zeppelins became very common in the early 1900s.Still, the employ of hydrogen for this purpose was largely discontinued around World War II after the explosion of The Hindenburg; this prompted greater apply of inert helium, rather than flammable hydrogen for air travel.
Video Showing the explosion of The Hindenburg. (Video from Youtube)
Recently, due to the fearfulness of fossil fuels running out, extensive research is being done on hydrogen every bit a source of energy.Considering of their moderately loftier energy densities liquid hydrogen and compressed hydrogen gas are possible fuels for the time to come.A huge reward in using them is that their combustion only produces water (information technology burns "make clean"). However, it is very costly, and non economically feasible with current engineering science.
Combustion of fuel produces free energy that can be converted into electrical energy when energy in the steam turns a turbine to bulldoze a generator. Nonetheless, this is not very efficient because a bully deal of energy is lost as oestrus. The production of electricity using voltaic cell tin can yield more electricity (a form of usable energy). Voltaic cells that transform chemical free energy in fuels (like Htwo and CH4) are called fuel cells. These are non self-contained and so are not considered batteries. The hydrogen cell is a type of fuel jail cell involving the reaction between H2(g) with O2(chiliad) to course liquid water; this cell is twice as efficient every bit the all-time internal combustion engine. In the cell (in bones conditions), the oxygen is reduced at the cathode, while the hydrogen is oxidized at the anode.
Reduction: O2(k)+2H2O(l)+4e- → 4OH-(aq)
Oxidation: H2(chiliad) + 2OH-(aq) → 2HiiO(l) + 2e-
Overall: 2Htwo(yard) + Oii(1000) → 2H2O(50)
E ° cell= Reduction- Oxidation= E ° O two /OH- - Eastward ° Water /H2 = 0.401V – (-0.828V) = +1.23
However, this engineering is far from being used in everyday life due to its great costs.
Image of A Hydrogen Fuel Prison cell. (Paradigm made by Ridhi Sachdev)
Natural Occurrence & Other Sources
Naturally Occurring Hydrogen
Hydrogen is the fuel for reactions of the Dominicus and other stars (fusion reactions). Hydrogen is the lightest and most abundant element in the universe. Well-nigh 70%- 75% of the universe is composed of hydrogen by mass. All stars are essentially large masses of hydrogen gas that produce enormous amounts of energy through the fusion of hydrogen atoms at their dense cores. In smaller stars, hydrogen atoms collided and fused to course helium and other light elements similar nitrogen and carbon(essential for life). In the larger stars, fusion produces the lighter and heavier elements like calcium, oxygen, and silicon.
On Earth, hydrogen is more often than not found in association with oxygen; its most arable form being water (H2O). Hydrogen is only .9% past mass and xv% by volume abundant on the earth, despite h2o covering about seventy% of the planet. Because hydrogen is and then light, there is just 0.5 ppm (parts per million) in the atmosphere, which is a good thing considering it is EXTREMELY flammable.
Other Sources of Hydrogen
Hydrogen gas can be prepared by reacting a dilute potent acid similar hydrochloric acids with an agile metal. The metal becomes oxides, while the H+ (from the acid) is reduced to hydrogen gas. This method is but practical for producing small amounts of hydrogen in the lab, only is much too plush for industrial production:
\[Zn_{(s)} + 2H^+_{(aq)} \rightarrow Zn^{2+}_{(aq)} + H_{2(g)}\]
The purest form of Hii(g) can come up from electrolysis of H2O(l), the most common hydrogen chemical compound on this constitute. This method is also not commercially viable because it requires a significant amount of energy (\(\Delta H = 572 \;kJ\)):
\[2H_2O_{(fifty)} \rightarrow 2H_{2(m)} + O_{ii(g)} \]
\(H_2O\) is the virtually abundant form of hydrogen on the planet, so information technology seems logical to attempt to extract hydrogen from h2o without electrolysis of water. To practice so, we must reduce the hydrogen with +1 oxidation state to hydrogen with 0 oxidation country (in hydrogen gas). Iii commonly used reducing agents are carbon (in coke or coal), carbon monoxide, and marsh gas. These react with water vapor form Htwo(one thousand):
\[C_{(south)} + 2H_2O_{(yard)} \rightarrow CO(g) + H_{2(grand)}\]
\[CO_{(g)} + 2H_2O_{(g)} \rightarrow CO2 + H_{2(g)}\]
Reforming of Marsh gas:
\[CH_{4(m)} + H_2O_{(g)} \rightarrow CO(g) + 3H_{two(thousand)}\]
These three methods are nearly industrially feasible (toll effective) methods of producing H2(m).
Isotopes
In that location are two important isotopes of hydrogen. Deuterium (twoH) has an abundance of 0.015% of terrestrial hydrogen and the nucleus of the isotope contains one neutron.
- Protium (1H) is the most common isotope, consisting of 99.98% of naturally occurring hydrogen. It is a nucleus containing a single proton.
- Deuterium (twoH ) is another an isotope containing a proton and neutron, consisting of only 0.0156% of the naturally occurring hydrogen. Commonly indicated with symbol D and sometimes called heavy hydrogen, deuterium is separated by the fractional distillation of liquid hydrogen but information technology can too be produced past the prolonged electrolysis of ordinary h2o. Approximately 100,000 gallons of water will produce a unmarried gallon of DiiO, "heavy water". This special kind of h2o has a higher density, melting indicate, and humid point than regular water and used as a moderator in some fission power reactors. Deuterium fuel is used in experimental fusion reactors. Replacing protium with deuterium has important uses for exploring reaction mechanisms via the kinetic isotope upshot.
- Tritium (threeH) contains two neutrons in its nucleus and is radioactive with a 12.3-year half-life, which is continuously formed in the upper temper due to catholic rays. Information technology is can also be made in a lab from Lithium-six in a nuclear reactor. Tritium is also used in hydrogen bombs. It is very rare (about i in every 1,018 atoms) and is formed in the environment past catholic ray bombardment. Most tritium is manufactured past bombarding Li with neutrons. Tritium is used in thermonuclear weapons and experimental fusion reactors.
References
- Shultz, M., Kelly, M., Paritsky, L., Wagner, J. A Theme-Based Grade: Hydrogen as the Fuel of the Future . Journal of Chemic Educational activity 2009 86 (ix), 105.
- Rigden, John. Hydrogen: The Essential Element . The President and Fellows of Harvard College. 2003.
- Banks, Alton. Hydrogen . Journal of Chemic Education 1989 66 (10), 801.
- Petrucci, Ralph H. General Chemistry . 9th ed. Upper Saddle River: Prentice Hall, 2007. Print
- Sadava, Heller, Orians, Purves, Hillis. Life The Science of Biology . 8th ed. Sunderland, MA: Due west.H. Freeman, 2008.
- Dinga, Grand. Hydrogen:The ultimate fuel and free energy carrier. Periodical of Chemic Education 1988 65 (8), 688.
Problems
- Write the reaction of Na(south) with H2(g).
- What is the proper name of the radioactive isotope of hydrogen?
- What characteristics of alkali metals does hydrogen display?
- What characteristics of halogens does hydrogen brandish?
- How does the electronegativity of hydrogen compare to that of the halogens?
- What is the electron configuration of a neutral hydrogen cantlet.
Answers
- 2Na(s) + Hii(g)→ 2NaH(s)
- Tritium
- Hydrogen is placed above group in the periodic tabular array because it has ns1 electron configuration like the alkali metals. However, information technology varies greatly from the brine metals as it forms cations (H+) more reluctantly than the other alkali metals. Hydrogen's ionization energy is 1312 kJ/mol, while lithium (the brine metal with the highest ionization free energy) has an ionization energy of 520 kJ/mol.
- Because hydrogen is a nonmetal and forms H- (hydride anions), it is sometimes placed above the halogens in the periodic table. Hydrogen likewise forms Hii dihydrogen like halogens. However, hydrogen is very different from the halogens. Hydrogen has a much smaller electron affinity than the halogens.
- Hydrogen is less electronegative than the halogens.
- 1sane
Contributors and Attributions
- Ridhi Sachdev (UC Davis)
Stephen R. Marsden
Source: https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Modules_and_Websites_%28Inorganic_Chemistry%29/Descriptive_Chemistry/Elements_Organized_by_Block/1_s-Block_Elements/Group__1:_The_Alkali_Metals/Z001_Chemistry_of_Hydrogen_%28Z1%29
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